reduce some mainform redundant menus for gb3/4x, they have the same logic as gbhawk link

src/BizHawk.Client.EmuHawk/MainForm.Designer.cs

@@ -285,10 +285,6 @@
 			this.DGBsettingsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
 			this.DGBHawkSubMenu = new System.Windows.Forms.ToolStripMenuItem();
 			this.DGBHawksettingsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
-			this.GB3xSubMenu = new System.Windows.Forms.ToolStripMenuItem();
-			this.GB3xsettingsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
-			this.GB4xSubMenu = new System.Windows.Forms.ToolStripMenuItem();
-			this.GB4xsettingsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
 			this.GGLSubMenu = new System.Windows.Forms.ToolStripMenuItem();
 			this.GGLsettingsToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
 			this.GenesisSubMenu = new System.Windows.Forms.ToolStripMenuItem();
@@ -450,8 +446,6 @@
             this.SaturnSubMenu,
             this.DGBSubMenu,
             this.DGBHawkSubMenu,
-			this.GB3xSubMenu,
-			this.GB4xSubMenu,
 			this.GGLSubMenu,
 			this.GenesisSubMenu,
 			this.wonderSwanToolStripMenuItem,
@@ -2550,36 +2544,6 @@
 			this.DGBHawksettingsToolStripMenuItem.Text = "Settings...";
 			this.DGBHawksettingsToolStripMenuItem.Click += new System.EventHandler(this.DgbHawkSettingsMenuItem_Click);
 			// 
-			// GB3xSubMenu
-			// 
-			this.GB3xSubMenu.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
-			this.GB3xsettingsToolStripMenuItem});
-			this.GB3xSubMenu.Name = "GB3xSubMenu";
-			this.GB3xSubMenu.Size = new System.Drawing.Size(68, 17);
-			this.GB3xSubMenu.Text = "&GB Link 3x";
-			// 
-			// GB3xsettingsToolStripMenuItem
-			// 
-			this.GB3xsettingsToolStripMenuItem.Name = "GB3xsettingsToolStripMenuItem";
-			this.GB3xsettingsToolStripMenuItem.Size = new System.Drawing.Size(125, 22);
-			this.GB3xsettingsToolStripMenuItem.Text = "Settings...";
-			this.GB3xsettingsToolStripMenuItem.Click += new System.EventHandler(this.GB3xSettingsMenuItem_Click);
-			// 
-			// GB4xSubMenu
-			// 
-			this.GB4xSubMenu.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
-			this.GB4xsettingsToolStripMenuItem});
-			this.GB4xSubMenu.Name = "GB4xSubMenu";
-			this.GB4xSubMenu.Size = new System.Drawing.Size(68, 17);
-			this.GB4xSubMenu.Text = "&GB Link 4x";
-			// 
-			// GB4xsettingsToolStripMenuItem
-			// 
-			this.GB4xsettingsToolStripMenuItem.Name = "GB4xsettingsToolStripMenuItem";
-			this.GB4xsettingsToolStripMenuItem.Size = new System.Drawing.Size(125, 22);
-			this.GB4xsettingsToolStripMenuItem.Text = "Settings...";
-			this.GB4xsettingsToolStripMenuItem.Click += new System.EventHandler(this.GB4xSettingsMenuItem_Click);
-			// 
 			// GGLSubMenu
 			// 
 			this.GGLSubMenu.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
@@ -3905,10 +3869,6 @@
 		private System.Windows.Forms.ToolStripMenuItem DGBsettingsToolStripMenuItem;
 		private System.Windows.Forms.ToolStripMenuItem DGBHawkSubMenu;
 		private System.Windows.Forms.ToolStripMenuItem DGBHawksettingsToolStripMenuItem;
-		private System.Windows.Forms.ToolStripMenuItem GB3xSubMenu;
-		private System.Windows.Forms.ToolStripMenuItem GB3xsettingsToolStripMenuItem;
-		private System.Windows.Forms.ToolStripMenuItem GB4xSubMenu;
-		private System.Windows.Forms.ToolStripMenuItem GB4xsettingsToolStripMenuItem;
 		private System.Windows.Forms.ToolStripMenuItem GGLSubMenu;
 		private System.Windows.Forms.ToolStripMenuItem GGLsettingsToolStripMenuItem;
 		private System.Windows.Forms.ToolStripMenuItem VectrexSubMenu;

src/BizHawk.Client.EmuHawk/MainForm.Events.cs

@@ -1933,16 +1933,6 @@ namespace BizHawk.Client.EmuHawk
 			GenericCoreConfig.DoDialog(this, "Gameboy Settings");
 		}
 
-		private void GB3xSettingsMenuItem_Click(object sender, EventArgs e)
-		{
-			GenericCoreConfig.DoDialog(this, "Gameboy Settings");
-		}
-
-		private void GB4xSettingsMenuItem_Click(object sender, EventArgs e)
-		{
-			GenericCoreConfig.DoDialog(this, "Gameboy Settings");
-		}
-
 		private void GgSettingsMenuItem_Click(object sender, EventArgs e)
 		{
 			GenericCoreConfig.DoDialog(this, "Game Gear Settings");

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -1826,8 +1826,6 @@ namespace BizHawk.Client.EmuHawk
 			SaturnSubMenu.Visible = false;
 			DGBSubMenu.Visible = false;
 			DGBHawkSubMenu.Visible = false;
-			GB3xSubMenu.Visible = false;
-			GB4xSubMenu.Visible = false;
 			GGLSubMenu.Visible = false;
 			GenesisSubMenu.Visible = false;
 			wonderSwanToolStripMenuItem.Visible = false;
@@ -1972,10 +1970,8 @@ namespace BizHawk.Client.EmuHawk
 					O2HawkSubMenu.Visible = true;
 					break;
 				case "GB3x":
-					GB3xSubMenu.Visible = true;
-					break;
 				case "GB4x":
-					GB4xSubMenu.Visible = true;
+					DGBHawkSubMenu.Visible = true;
 					break;
 				case "MAME":
 					arcadeToolStripMenuItem.Visible = true;