reset: hi6220: Set module license so that it can be loaded

The hi6220_reset driver can be built as a standalone module
yet it cannot be loaded because it depends on GPL exported symbols.

Lets set the module license so that the module loads, and things like
the on-board kirin drm starts working.

Signed-off-by: Jeremy Linton <lintonrjeremy@gmail.com>
Reviewed-by: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>