radv: emit esgs ring size in one place.

radv: emit esgs ring size in one place.

This register is the same on all gpus so far, so emit it in one
place and also for the pre-gfx9 gpus set the value in the pipeline
creation.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>