radeonsi: add helper to use si_screen::aux_context
This context needs to be locked before usage, and flushed after. If it's forgotten, radeonsi may crash (eg #6666 (closed)).
To avoid this kind of error, introduce 2 helpers.
cc: mesa-stable
This context needs to be locked before usage, and flushed after. If it's forgotten, radeonsi may crash (eg #6666 (closed)).
To avoid this kind of error, introduce 2 helpers.
cc: mesa-stable