dt-bindings: arm: sunxi: add PineTab Early Adopter edition

Early adopter's PineTabs (and further releases) will have a new LCD
panel different with the one that is used when in development (because
the old panel's supply discontinued).

Add a new DT compatible for it.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201224024001.19248-1-icenowy@aosc.io

Documentation/devicetree/bindings/arm/sunxi.yaml

@@ -700,6 +700,11 @@ properties:
           - const: pine64,pinetab
           - const: allwinner,sun50i-a64
 
+      - description: Pine64 PineTab, Early Adopter's batch (and maybe later ones)
+        items:
+          - const: pine64,pinetab-early-adopter
+          - const: allwinner,sun50i-a64
+
       - description: Pine64 SoPine Baseboard
         items:
           - const: pine64,sopine-baseboard