IB/mlx4: Fix value of pkey_index in QP1 completions

Fix the value of pkey_index in completions to get a valid value for
GSI QPs.  Without this fix, incoming GSI packets on port 2 get an
invalid P_Key index in the completion, which prevents the MAD layer
from sending back a response, which can make the second port of
ConnectX HCAs completely useless.
Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/cq.c

@@ -430,7 +430,7 @@ static int mlx4_ib_poll_one(struct mlx4_ib_cq *cq,
 		wc->dlid_path_bits = (be32_to_cpu(cqe->g_mlpath_rqpn) >> 24) & 0x7f;
 		wc->wc_flags      |= be32_to_cpu(cqe->g_mlpath_rqpn) & 0x80000000 ?
 			IB_WC_GRH : 0;
-		wc->pkey_index     = be32_to_cpu(cqe->immed_rss_invalid) >> 16;
+		wc->pkey_index     = be32_to_cpu(cqe->immed_rss_invalid) & 0x7f;
 	}
 
 	return 0;