glapi: Mark compressed teximage functions as sync.

glapi: Mark compressed teximage functions as sync.

Without doing some additional tracking, we won't know whether the data
will be immediate user data, or will be loaded from a PBO.  The normal
teximage functions will be sync by default because they don't know up
front what the size of their image data is.  But for compressed teximage,
we have the count information, so they would end up async by default.

Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Acked-by: Marek Olšák <maraeo@gmail.com>
Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>
Tested-by: Mike Lothian <mike@fireburn.co.uk>