ARM: dts: sun8i: Add mmc2_8bit_pins to sun8i-h3.dtsi

Add a pinctrl node for mmc2 in 8 bits mode on H3 SoCs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>