dt-bindings: power: amlogic, meson-gx-pwrc: Add G12A compatible

The Amlogic G12A has a slighly different Power Control, but uses the
same address space and sysctrl registers.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

Documentation/devicetree/bindings/power/amlogic,meson-gx-pwrc.txt

@@ -16,7 +16,9 @@ Device Tree Bindings:
 ---------------------
 
 Required properties:
-- compatible: should be "amlogic,meson-gx-pwrc-vpu" for the Meson GX SoCs
+- compatible: should be one of the following :
+	- "amlogic,meson-gx-pwrc-vpu" for the Meson GX SoCs
+	- "amlogic,meson-g12a-pwrc-vpu" for the Meson G12A SoCs
 - #power-domain-cells: should be 0
 - amlogic,hhi-sysctrl: phandle to the HHI sysctrl node
 - resets: phandles to the reset lines needed for this power demain sequence