IB/usnic: check for allocation failure

usnic_uiom_get_dev_list() can return ERR_PTR(-ENOMEM) so we should check
for that.

Fixes: e3cf00d0a8 ("IB/usnic: Add Cisco VIC low-level hardware driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/usnic/usnic_ib_verbs.c

@@ -164,6 +164,8 @@ find_free_vf_and_create_qp_grp(struct usnic_ib_dev *us_ibdev,
 	if (usnic_ib_share_vf) {
 		/* Try to find resouces on a used vf which is in pd */
 		dev_list = usnic_uiom_get_dev_list(pd->umem_pd);
+		if (IS_ERR(dev_list))
+			return ERR_CAST(dev_list);
 		for (i = 0; dev_list[i]; i++) {
 			dev = dev_list[i];
 			vf = pci_get_drvdata(to_pci_dev(dev));