ARM: dts: sun8i: h3: fix ALL-H3-CC H3 ver VDD-CPUX voltage

The VDD-CPUX voltage of ALL-H3-CC H3 ver should be 1.2V, not the 3.3V
currently defined in the device tree.

Fix the voltage in the device tree.

Fixes: 6ca35864 ("ARM: dts: sun8i: h3: Add dts file for Libre Computer Board ALL-H3-CC H3 ver.")
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Cc: <stable@vger.kernel.org> # 4.16.x
Signed-off-by: Chen-Yu Tsai <wens@csie.org>