mthca_create_ah() includes the port number in the GID index. The reverse
needs to be done in mthca_read_ah().
Noted by Hal Rosenstock.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
                        ah->av->sl_tclass_flowlabel & cpu_to_be32(0xfffff);
                ib_get_cached_gid(&dev->ib_dev,
                                  be32_to_cpu(ah->av->port_pd) >> 24,
-                                 ah->av->gid_index,
+                                 ah->av->gid_index % dev->limits.gid_table_len,
                                  &header->grh.source_gid);
                memcpy(header->grh.destination_gid.raw,
                       ah->av->dgid, 16);