octeontx2-af: Support for NIXLF's UCAST/PROMISC/ALLMULTI modes

By default NIXLF is set in UCAST mode. This patch adds a new
mailbox message which when sent by a RVU PF changes this default
mode. When promiscuous mode is needed, the reserved promisc entry
for each of RVU PF is setup to match against ingress channel number
only, so that all pkts on that channel are accepted and forwarded
to the mode change requesting PF_FUNC's NIXLF.

PROMISC and ALLMULTI modes are supported only for PFs, for VFs only
UCAST mode is supported.

Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>