ARM: dts: sun8i: sinlinx-sina33: Add AXP223 PMIC device and regulator nodes

This board has a X-Powers AXP223 PMIC connected via RSB. Its regulators
provide power to various parts of the SoC and the board.

Also update the regulator supply phandles.

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