be2net: Avoid double insertion of vlan tags.

Fix to avoid double insertion of  vlan tags into the packet while
handling an asic workaroud (issue introduced by net next Commit bc0c3405)

Signed-off-by: Sarveshwar Bandi <sarveshwar.bandi@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>