ARM: sunxi: Convert pinctrl nodes to generic bindings

Now that we can handle the generic pinctrl bindings, convert our DT to it.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>