Prevent trying to use DirectInput on Linux (resolves #2607)

src/BizHawk.Client.EmuHawk/Input/Input.cs

@@ -123,6 +123,7 @@ namespace BizHawk.Client.EmuHawk
 			Adapter = config.HostInputMethod switch
 			{
 				EHostInputMethod.OpenTK => new OpenTKInputAdapter(),
+				_ when OSTailoredCode.IsUnixHost => new OpenTKInputAdapter(),
 				EHostInputMethod.DirectInput => new DirectInputAdapter(),
 				_ => throw new Exception()
 			};