octeontx2-af: Fix promiscuous mode

CN10KB silicon introduced a new exact match feature,
which is used for DMAC filtering. The state of installed
DMAC filters in this exact match table is getting corrupted
when promiscuous mode is toggled. Fix this by not touching
Exact match related config when promiscuous mode is toggled.

Fixes: 2dba9459

 ("octeontx2-af: Wrapper functions for MAC addr add/del/update/reset")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>