ARM: dts: sunxi: h3-h5: rename mmc0_pins_a and mmc1_pins_a

There is only one pinctrl configuration for mmc0 and mmc1 so let's
drop the _a suffix from both of them.

Signed-off-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>