MMIO: Port the SW CP/PE MMIOs to the new interface.

Migration is now complete.

Source/Core/VideoBackends/Software/SWmain.cpp

@@ -362,12 +362,12 @@ void VideoSoftware::Video_AbortFrame(void)
 
 void VideoSoftware::RegisterCPMMIO(MMIO::Mapping* mmio, u32 base)
 {
-	// TODO
+	SWCommandProcessor::RegisterMMIO(mmio, base);
 }
 
 void VideoSoftware::RegisterPEMMIO(MMIO::Mapping* mmio, u32 base)
 {
-	// TODO
+	SWPixelEngine::RegisterMMIO(mmio, base);
 }
 
 readFn16 VideoSoftware::Video_CPRead16()