Handle BP mask register better to avoid useless BP writes (causing fl…

…ushes)

Patch from konpie: http://forums.dolphin-emulator.com/showthread.php?tid=24658

Source/Core/VideoCommon/Src/BPMemory.cpp

@@ -19,15 +19,18 @@ void LoadBPReg(u32 value0)
 	int opcode = value0 >> 24;
 	int oldval = ((u32*)&bpmem)[opcode];
 	int newval = (oldval & ~bpmem.bpMask) | (value0 & bpmem.bpMask);
-	int changes = (oldval ^ newval) & 0xFFFFFF;
 
-	BPCmd bp = {opcode, changes, newval};
-
-	//reset the mask register
 	if (opcode != 0xFE)
+	{
+		//reset the mask register
 		bpmem.bpMask = 0xFFFFFF;
 
-	BPWritten(bp);
+		int changes = (oldval ^ newval) & 0xFFFFFF;
+		BPCmd bp = {opcode, changes, newval};
+		BPWritten(bp);
+	}
+	else
+		bpmem.bpMask = newval;
 }
 
 void GetBPRegInfo(const u8* data, char* name, size_t name_size, char* desc, size_t desc_size)