bnx2x: Allow vfs to disable txvlan offload

[ Upstream commit 92f85f05 ]

VF clients are configured as enforced, meaning firmware is validating
the correctness of their ethertype/vid during transmission.
Once txvlan is disabled, VF would start getting SKBs for transmission
here vlan is on the payload - but it'll pass the packet's ethertype
instead of the vid, leading to firmware declaring it as malicious.

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>