We need to unlock here before returning -EINVAL.

Fixes: 6ca5274d ('pinctrl: rockchip: add rk3188 specifics')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>