HID: nvidia-shield: Introduce thunderstrike_destroy()

In order to simplify some error handling paths and avoid code duplication,
introduce thunderstrike_destroy() which undoes thunderstrike_create().

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>