mesa/st: ETC2 now uses R8G8B8A8_SRGB as fallback
The check for ETC2 compatibility was not updated when the fallback format was changed. Fixes: 71867a0a st/mesa: Fall back to R8G8B8A8_SRGB for ETC2 Signed-off-by:Gert Wollny <gert.wollny@collabora.com> Reviewed-by:
Marek Olšák <marek.olsak@amd.com> (cherry picked from commit e94095ec)