On GLES hosts, pixel data for BGRA resources are byte-reordered and
passed to the host driver for compatibility reasons.
The clear color used in glClearTexSubImage[EXT] for such resources
on GLES hosts must be reordered to match.
Signed-off-by: Ryan Neph <ryanneph@google.com>
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/725>