iw_cxgb4: Fix error return code in c4iw_rdev_open()

commit 15f7e3c2 upstream.

Fix to return error code -ENOMEM from the __get_free_page() error
handling case instead of 0, as done elsewhere in this function.

Fixes: 05eb2389 ("cxgb4/iw_cxgb4: Doorbell Drop Avoidance Bug Fixes")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/infiniband/hw/cxgb4/device.c

@@ -694,6 +694,7 @@ static int c4iw_rdev_open(struct c4iw_rdev *rdev)
 			    __get_free_page(GFP_KERNEL);
 	if (!rdev->status_page) {
 		pr_err(MOD "error allocating status page\n");
+		err = -ENOMEM;
 		goto err4;
 	}
 	rdev->status_page->db_off = 0;