bnx2x: Don't allow VFs to become promiscuous

Currently, if a VF's Rx Mode will be configured to support promiscuous mode
the PF will comply, causing the VF to actually become promiscuous.
This will enable the VF to see all unicast traffic which might be intended for
other VMs, which we believe should not be possible.

This patch will cause the hypervisor to ignore the VF's request for changes in
its Rx mode (other than disabling it), preventing it from becoming promiscuous.

Reported-by: Yoann Juet <yoann.juet@univ-nantes.fr>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>