ARM: dts: sun8i: Fix pio nodes Orangepi Plus dts

Fix sun8i-h3-orangepi-plus.dts:
1) Having 2 pio nodes, by merging these into one
2) Having the pio and r_pio nodes before the mmc nodes, while they
   should be sorted by alphabet

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