usbip: usbip_host: run rebind from exit when module is removed

After removing usbip_host module, devices it releases are left without
a driver. For example, when a keyboard or a mass storage device are
bound to usbip_host when it is removed, these devices are no longer
bound to any driver.

Fix it to run device_attach() from the module exit routine to restore
the devices to their original drivers. This includes cleanup changes
and moving device_attach() code to a common routine to be called from
rebind_store() and usbip_host_exit().

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c
index 7813c18..9d04251 100644
--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -448,12 +448,8 @@ static void stub_disconnect(struct usb_device *udev)
 	busid_priv->sdev = NULL;
 	stub_device_free(sdev);
 
-	if (busid_priv->status == STUB_BUSID_ALLOC) {
+	if (busid_priv->status == STUB_BUSID_ALLOC)
 		busid_priv->status = STUB_BUSID_ADDED;
-	} else {
-		busid_priv->status = STUB_BUSID_OTHER;
-		del_match_busid((char *)udev_busid);
-	}
 }
 
 #ifdef CONFIG_PM