This driver forgets to unregister controller when remove.
Use devm API to unregister it automatically to fix it.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Link: https://lore.kernel.org/r/20191109075517.29988-1-hslester96@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>