[SI] add a way to check if the current controller is a gcpad

(or gcpad-compatible)

Source/Core/Core/HW/SI_Device.cpp

@@ -67,6 +67,26 @@ public:
 };
 
 
+// Check if a device class is inheriting from CSIDevice_GCController
+// The goal of this function is to avoid special casing a long list of
+// device types when there is no "real" input device, e.g. when playing
+// a TAS movie, or netplay input.
+bool SIDevice_IsGCController(SIDevices type)
+{
+	switch (type)
+	{
+	case SIDEVICE_GC_CONTROLLER:
+	case SIDEVICE_WIIU_ADAPTER:
+	case SIDEVICE_GC_TARUKONGA:
+	case SIDEVICE_DANCEMAT:
+	case SIDEVICE_GC_STEERING:
+		return true;
+	default:
+		return false;
+	}
+}
+
+
 // F A C T O R Y
 std::unique_ptr<ISIDevice> SIDevice_Create(const SIDevices device, const int port_number)
 {

Source/Core/Core/HW/SI_Device.h

@@ -107,4 +107,6 @@ public:
 	}
 };
 
+bool SIDevice_IsGCController(SIDevices type);
+
 std::unique_ptr<ISIDevice> SIDevice_Create(const SIDevices device, const int port_number);