radv: Record a PM4 sequence for graphics pipeline switches.

radv: Record a PM4 sequence for graphics pipeline switches.

This gives about 2% performance improvement on dota2 for me.

This is mostly a mechanical copy and replacement, but at bind time
we still do:

1) Some stuff that is only based on num_samples changes.
2) Some command buffer state setting.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>