ARM: dts: sunxi: h3/h5: Remove stale pinctrl-names entry

Some nodes still have pinctrl-names entry, yet they don't have any pinctrl
group anymore. Drop them.

Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>