USB: cdc-wdm: make module autoload work

this fixes an omission that led to no alias being computed for the
cdc-wdm module.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/cdc-wdm.c

@@ -42,6 +42,8 @@ static struct usb_device_id wdm_ids[] = {
 	{ }
 };
 
+MODULE_DEVICE_TABLE (usb, wdm_ids);
+
 #define WDM_MINOR_BASE	176