USB: Remove test for NULL that'll never happen in usb_disconnect()

In drivers/usb/core/hub.c::usb_disconnect(), 'udev' will never be
NULL, so remove the test and printing of debug message.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

@@ -1636,11 +1636,6 @@ void usb_disconnect(struct usb_device **pdev)
 	int			i;
 	struct usb_hcd		*hcd = bus_to_hcd(udev->bus);
 
-	if (!udev) {
-		pr_debug ("%s nodev\n", __func__);
-		return;
-	}
-
 	/* mark the device as inactive, so any further urb submissions for
 	 * this device (and any of its children) will fail immediately.
 	 * this quiesces everything except pending urbs.