HID: lenovo-tpkbd: Fix memory leak in tpkbd_remove_tp()

We need to kfree names for led_mute and led_micmute in tpkbd_remove_tp().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Bernhard Seibold <mail@bernhard-seibold.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>