qed: Prevent VF from Tx-switching 'promisc'

Internal loopback in driver is based on two things - first
is the willingness of transmitter to use it [in case of VFs,
this can be forced based on VEPA/VEB] and secondly on another
vport classification configuration which should match the
packet's destination.

Current code allows non-linux VFs to configure a 'promisc'
mode on Tx, meaning all traffic sent by VF would be loopbacked
internally by firmware; This isn't considered a valid mode and
as such should be prevented by PF.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>