RDMA/cxgb4: set error code on kmalloc() failure

If kmalloc() fails in c4iw_alloc_ucontext(), the function
leaves but does not set an error code in ret variable:
it will return 0 to the caller.

This patch set ret to -ENOMEM in such case.

Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Steve Wise <swise@chelsio.com>
Signed-off-by: NYann Droneaud <ydroneaud@opteya.com>
Acked-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/infiniband/hw/cxgb4/provider.c

@@ -128,8 +128,10 @@ static struct ib_ucontext *c4iw_alloc_ucontext(struct ib_device *ibdev,
 		rhp->rdev.flags |= T4_STATUS_PAGE_DISABLED;
 	} else {
 		mm = kmalloc(sizeof(*mm), GFP_KERNEL);
-		if (!mm)
+		if (!mm) {
+			ret = -ENOMEM;
 			goto err_free;
+		}
 
 		uresp.status_page_size = PAGE_SIZE;