drm/i915: support 32 bit BGR formats in sprite planes

intel_framebuffer_init does some basic sanity checking of the pixel format,
but is used by the plane code in addition to the primary crtc.  So it
needs to contain any formats used in either place.

Add the XBGR8888 format to the checklist so the plane code can use it.
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NKeith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_display.c

@@ -7828,6 +7828,7 @@ int intel_framebuffer_init(struct drm_device *dev,
 	case DRM_FORMAT_RGB332:
 	case DRM_FORMAT_RGB565:
 	case DRM_FORMAT_XRGB8888:
+	case DRM_FORMAT_XBGR8888:
 	case DRM_FORMAT_ARGB8888:
 	case DRM_FORMAT_XRGB2101010:
 	case DRM_FORMAT_ARGB2101010: