Remove all refrences of field ordering from video backends.

They were unused.

Source/Plugins/Plugin_VideoSoftware/Src/SWmain.cpp

@@ -187,7 +187,7 @@ void VideoSoftware::Video_Prepare()
 }
 
 // Run from the CPU thread (from VideoInterface.cpp)
-void VideoSoftware::Video_BeginField(u32 xfbAddr, FieldType field, u32 fbWidth, u32 fbHeight)
+void VideoSoftware::Video_BeginField(u32 xfbAddr, u32 fbWidth, u32 fbHeight)
 {	
 }
 

Source/Plugins/Plugin_VideoSoftware/Src/VideoBackend.h

@@ -25,7 +25,7 @@ class VideoSoftware : public VideoBackend
 
 	void Video_EnterLoop();
 	void Video_ExitLoop();
-	void Video_BeginField(u32, FieldType, u32, u32);
+	void Video_BeginField(u32, u32, u32);
 	void Video_EndField();
 	
 	u32 Video_AccessEFB(EFBAccessType, u32, u32, u32);