bnx2: Correctly receive full sized 802.1ad fragmes

This driver, similar to tg3, has a check that will
cause full sized 802.1ad frames to be dropped.  The
frame will be larger then the standard mtu due to the
presense of vlan header that has not been stripped.
The driver should not drop this frame and should process
it just like it does for 802.1q.

CC: Sony Chacko <sony.chacko@qlogic.com>
CC: Dept-HSGLinuxNICDev@qlogic.com
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>