IB/mlx4: Add dependency INET

Since mlx4_ib supports IP based addressing, a dependency on INET needs
to be added, since mlx4_ib registers itself for net device events.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

drivers/infiniband/hw/mlx4/Kconfig

 config MLX4_INFINIBAND
 	tristate "Mellanox ConnectX HCA support"
-	depends on NETDEVICES && ETHERNET && PCI
+	depends on NETDEVICES && ETHERNET && PCI && INET
 	select NET_VENDOR_MELLANOX
 	select MLX4_CORE
 	---help---