freedreno/a3xx: reinstate rgb10_a2ui texture format

freedreno/a3xx: reinstate rgb10_a2ui texture format

Rendering doesn't work, but having the format in place avoids an assert
when selecting the texture format in st_format. I believe it's required
for GLES3, so more tracing is required to determine what bit we're
missing to make rendering work.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5073>