bnx2x: fix possible overrun of VFPF multicast addresses array

[ Upstream commit 22118d86 ]

It is too late to check for the limit of the number of VF multicast
addresses after they have already been copied to the req->multicast[]
array, possibly overflowing it.

Do the check before copying.

Also fix the error path to not skip unlocking vf2pf_mutex.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>