octeontx2-af: CN10KB: fix PFC configuration

octeontx2-af: CN10KB: fix PFC configuration

Suppose user has enabled pfc with prio 0,1 on a PF netdev(eth0)
	dcb pfc set dev eth0 prio-pfc o:on 1:on
later user enabled pfc priorities 2 and 3 on the VF interface(eth1)
	dcb pfc set dev eth1 prio-pfc 2:on 3:on

Instead of enabling pfc on all priorities (0..3), the driver only
enables on priorities 2,3. This patch corrects the issue by using
the proper CSR address.

Fixes: b9d0fedc6234 ("octeontx2-af: cn10kb: Add RPM_USX MAC support")
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230824081032.436432-3-sumang@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>