HID: asus: Stop underlying hardware on remove

We are missing a call to hid_hw_stop() on the remove hook.
Among other things this is causing an Oops when (re-)starting GNOME /
upowerd / ... after the module has been already rmmod-ed.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>