arm64: dts: allwinner: sort the nodes in sun50i-a64-pine64.dts

In this dts file, uart0 node is put before i2c1.

Move the uart0 node to the end to satisfy alphebetical order.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>