IB/usnic: Fix locking when unregistering

Move the call to usnic_ib_device_remove after usnic_ib_ibdev_list_lock has
been released.
Signed-off-by: Parvi Kaustubhi <pkaustub@cisco.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/usnic/usnic_ib_main.c

@@ -470,15 +470,17 @@ static void usnic_ib_undiscover_pf(struct kref *kref)
 				&usnic_ib_ibdev_list, ib_dev_link) {
 		if (us_ibdev->pdev == dev) {
 			list_del(&us_ibdev->ib_dev_link);
-			usnic_ib_device_remove(us_ibdev);
 			found = true;
 			break;
 		}
 	}
 
-	WARN(!found, "Failed to remove PF %s\n", pci_name(dev));
 
 	mutex_unlock(&usnic_ib_ibdev_list_lock);
+	if (found)
+		usnic_ib_device_remove(us_ibdev);
+	else
+		WARN(1, "Failed to remove PF %s\n", pci_name(dev));
 }
 
 static struct usnic_ib_dev *usnic_ib_discover_pf(struct usnic_vnic *vnic)