radv/amdgpu: Only wait on queue_syncobj when needed.

radv/amdgpu: Only wait on queue_syncobj when needed.

If signalled on the same queue it is totally useless, so only wait
if we have a syncobj that is explicitly being waited on, which can
be from potentially another queue/ctx. (Ideally we'd check but there
is no way to do so currently. Might revisit when we integrate the
common sync framework)

Fixes: 7675d066caa ("radv/amdgpu: Add support for submitting 0 commandbuffers.")
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14214>