be2net: Fix to receive Multicast Packets when Promiscuous mode is enabled on certain devices

When a user requests Promiscuous mode on SkyHawk-R devices,
the FW enables Desparate Promiscuous mode.
Due to this, we need to explicitly enable Multicast Promiscuous mode
so that Multicast packets are received as well.

This patch fixes that.

Signed-off-by: Ajit Khaparde <ajit.khaparde@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>