dt-bindings: arm: sunxi: Add PinePhone 1.2 bindings

Document board compatible names for Pine64 PinePhone 1.2.
Signed-off-by: Ondrej Jirman <megous@megous.com>
Link: https://lore.kernel.org/r/20200703194842.111845-2-megous@megous.comSigned-off-by: Maxime Ripard <maxime@cerno.tech>

Documentation/devicetree/bindings/arm/sunxi.yaml

@@ -657,6 +657,11 @@ properties:
           - const: pine64,pinephone-1.1
           - const: allwinner,sun50i-a64
 
+      - description: Pine64 PinePhone (1.2)
+        items:
+          - const: pine64,pinephone-1.2
+          - const: allwinner,sun50i-a64
+
       - description: Pine64 PineTab
         items:
           - const: pine64,pinetab