SNES: Set internal palette address to 0 when outputting bg color (whe…

…n no layers have visible pixels)

This fixes regressions in PGA Tour Golf and Mini Yonku Shining Scorpion. These games attempt to write to CGRAM during rendering, but at a time where the background color is being rendered, so the writes overwrite address 0 in CGRAM. Without this fix, the last non-transparent pixel's color address was being used, causing it to corrupt the wrong color in CGRAM (which caused the glitches)

Core/SNES/SnesPpu.cpp

@@ -925,10 +925,12 @@ void SnesPpu::RenderBgColor()
 	uint8_t pixelFlags = (_state.ColorMathEnabled & 0x20) ? PixelFlags::AllowColorMath : 0;
 	for(int x = _drawStartX; x <= _drawEndX; x++) {
 		if((_mainScreenFlags[x] & 0x0F) == 0) {
+			_state.InternalCgramAddress = 0;
 			_mainScreenBuffer[x] = _cgram[0];
 			_mainScreenFlags[x] = pixelFlags;
 		}
 		if(_subScreenPriority[x] == 0) {
+			_state.InternalCgramAddress = 0;
 			_subScreenBuffer[x] = _cgram[0];
 		}
 	}