octeontx2-af: devlink configuration support

CN10KB silicon supports Exact match feature. This feature can be disabled
through devlink configuration. Devlink command fails if DMAC filter rules
are already present. Once disabled, legacy RPM based DMAC filters will be
configured.

Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>