egl/x11: Re-allocate buffers if format is suboptimal

egl/x11: Re-allocate buffers if format is suboptimal

If PresentCompleteNotify event says the pixmap was presented
with mode PresentCompleteModeSuboptimalCopy, it means the pixmap
could possibly have been flipped instead if allocated with a
different format/modifier.

Signed-off-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>