radv: Use correct flush bits for flushing L2 during CB/DB flushes.

Copied from radeonsi.

Putting in the correct metadata flush commands for eventually not
flushing L2 on CB/DB switch.

Does not remove the need for V_028A90_CACHE_FLUSH_AND_INV_TS_EVENT
at the moment.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
1 file changed