ARM: dts: sun8i: h2-plus: Sort dtb entries in Makefile

The dtb entry for the Banana Pi M2 Zero in the device tree makefile
somehow ended up in between two Orange Pi boards.

Move it so the list is properly sorted.

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