As we added A20 support to A10 pinctrl driver, now we can delete the
dedicated A20 pinctrl driver, which is duplicated code.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.io>
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
[Drop Makefile entry]
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>