ibmvnic: Refresh device multicast list after reset

[ Upstream commit be32a243

 ]

It was observed that multicast packets were no longer received after
a device reset.  The fix is to resend the current multicast list to
the backing device after recovery.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>