IB/mlx5: Return error for unsupported signature type

In case of unsupported singature, we returned positive
value, while the better approach is to return -EINVAL.

In addition, in this change, the error print is enriched
to provide an actual supplied signature type.

Fixes: e663181 ("IB/mlx5: Support IB_WR_REG_SIG_MR")
Cc: Sagi Grimberg <sagi@grimberg.me>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/qp.c

@@ -3637,8 +3637,9 @@ static int set_psv_wr(struct ib_sig_domain *domain,
 		psv_seg->ref_tag = cpu_to_be32(domain->sig.dif.ref_tag);
 		break;
 	default:
-		pr_err("Bad signature type given.\n");
-		return 1;
+		pr_err("Bad signature type (%d) is given.\n",
+		       domain->sig_type);
+		return -EINVAL;
 	}
 
 	*seg += sizeof(*psv_seg);