enic: Do not advertise NETIF_F_HW_VLAN_RX

Hardware does not honor vlan filters from the host and so the driver does
not need to advertise this.

Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: Vasanthy Kolluri <vkolluri@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>