Relax level check when looking for USB2/3 dual hubs

Some devices (notably Raspberry 4B) have USB3 hub that advertises
its USB2 compatibility partner at different depth level.
Raspberry 4B onboard hub doesn't yet support uhubctl directly
(but it should once https://github.com/raspberrypi/linux/issues/3079 is fixed),
but this breaks level check restriction for any external USB3 hub attached to RPi4B
- so this check has been removed.

uhubctl.c

@@ -754,10 +754,6 @@ static int usb_find_hubs()
                 if (hubs[i].nports != hubs[j].nports)
                     continue;
 
-                /* And the same level: */
-                if (hubs[i].level != hubs[j].level)
-                    continue;
-
                 /* Finally, we claim a match: */
                 match = j;
                 break;