net/mlx4_core: Disable Granular QoS per VF under IB/Eth VPI configuration

Due to firmware bug, under VPI configuration when port1 = IB and
port2 = Eth, Granular QoS per VF isn't working properly. More over,
the whole QP0/QP1 Para-Virtualization in the mlx4 IB driver is
broken on that config.

Hence, we must disable Granular QoS per VF under that configuration
till a fix is introduced. Once that happens, a new device capability
will be used to mark the feature support on that specific configuration.

Reported-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>