pinctrl: generic: rename input schmitt disable

Rename PIN_CONFIG_INPUT_SCHMITT_DISABLE to
PIN_CONFIG_INPUT_SCHMITT_ENABLE. It's used to make it more generialize.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>