In Marvell PXA/MMP silicons, input schmitt disable value is 0x40, not 0.
So append new config parameter -- input schmitt disable.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>