IB/core: Add netdev and gid attributes paramteres to cache

Adding an ability to query the IB cache by a netdev and get the
attributes of a GID. These parameters are necessary in order to
successfully resolve the required GID (when the netdevice is known)
and get the Ethernet L2 attributes from a GID.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mthca/mthca_av.c

@@ -281,7 +281,7 @@ int mthca_read_ah(struct mthca_dev *dev, struct mthca_ah *ah,
 		ib_get_cached_gid(&dev->ib_dev,
 				  be32_to_cpu(ah->av->port_pd) >> 24,
 				  ah->av->gid_index % dev->limits.gid_table_len,
-				  &header->grh.source_gid);
+				  &header->grh.source_gid, NULL);
 		memcpy(header->grh.destination_gid.raw,
 		       ah->av->dgid, 16);
 	}