Implement BGRA8 framebuffer format

src/video_core/gpu.cpp

@@ -16,6 +16,7 @@ namespace Tegra {
 u32 FramebufferConfig::BytesPerPixel(PixelFormat format) {
     switch (format) {
     case PixelFormat::ABGR8:
+    case PixelFormat::BGRA8:
         return 4;
     default:
         return 4;