IB/mlx4: Enable debug print of SMPs

IB Subnet Management Packets (SMPs) were excluded from debug prints.

Fixed by enabling print even on QP0 MADs.
Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx4/mad.c

@@ -807,7 +807,7 @@ static int ib_process_mad(struct ib_device *ibdev, int mad_flags, u8 port_num,
 	int err;
 	struct ib_port_attr pattr;
 
-	if (in_wc && in_wc->qp->qp_num) {
+	if (in_wc && in_wc->qp) {
 		pr_debug("received MAD: slid:%d sqpn:%d "
 			"dlid_bits:%d dqpn:%d wc_flags:0x%x, cls %x, mtd %x, atr %x\n",
 			in_wc->slid, in_wc->src_qp,