usb: core: switch bus numbering to using idr

USB bus numbering is based on directly dealing with bitmaps and
defines a separate list of busses.
This can be simplified and unified by using existing idr functionality.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/r8a66597-hcd.c

@@ -2099,13 +2099,8 @@ static void r8a66597_check_detect_child(struct r8a66597 *r8a66597,
 
 	memset(now_map, 0, sizeof(now_map));
 
-	list_for_each_entry(bus, &usb_bus_list, bus_list) {
-		if (!bus->root_hub)
-			continue;
-
-		if (bus->busnum != hcd->self.busnum)
-			continue;
-
+	bus = idr_find(&usb_bus_idr, hcd->self.busnum);
+	if (bus && bus->root_hub) {
 		collect_usb_address_map(bus->root_hub, now_map);
 		update_usb_address_map(r8a66597, bus->root_hub, now_map);
 	}