IB/i40iw: Fix error code in i40iw_create_cq()

We accidentally forgot to set the error code if ib_copy_from_udata()
fails.  It means we return ERR_PTR(0) which is NULL and results in a
NULL dereference in the callers.

Fixes: d3749841 ("i40iw: add files for iwarp interface")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NShiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/hw/i40iw/i40iw_verbs.c

@@ -1168,8 +1168,10 @@ static struct ib_cq *i40iw_create_cq(struct ib_device *ibdev,
 		memset(&req, 0, sizeof(req));
 		iwcq->user_mode = true;
 		ucontext = to_ucontext(context);
-		if (ib_copy_from_udata(&req, udata, sizeof(struct i40iw_create_cq_req)))
+		if (ib_copy_from_udata(&req, udata, sizeof(struct i40iw_create_cq_req))) {
+			err_code = -EFAULT;
 			goto cq_free_resources;
+		}
 
 		spin_lock_irqsave(&ucontext->cq_reg_mem_list_lock, flags);
 		iwpbl = i40iw_get_pbl((unsigned long)req.user_cq_buffer,