pinctrl: mediatek: simplify the return expression of mtk_pinconf_bias_disable_set_rev1()

Simplify the return expression.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20201210135902.1548-1-zhengyongjun3@huawei.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>