bnx2x: fix VLAN configuration for VFs.

If the hypervisor configures a vlan for the VF via the PF, the expected
result is that only packets tagged by said vlan will be received by the VF
(and that vlan will be silently removed).
Due to an incorrect manipulation of vlan filters in the driver, the
VF can receive untagged traffic even if the hypervisor configured
some vlan for it.

This patch corrects the behaviour.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>