dt-bindings: arm: sunxi: document orig PineTab DT as sample

As the original PineTab DT (which uses sun50i-a64-pinetab name) is only
for development samples, document this.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201224024138.19422-1-icenowy@aosc.io

Documentation/devicetree/bindings/arm/sunxi.yaml

@@ -695,7 +695,7 @@ properties:
           - const: pine64,pinephone-1.2
           - const: allwinner,sun50i-a64
 
-      - description: Pine64 PineTab
+      - description: Pine64 PineTab, Development Sample
         items:
           - const: pine64,pinetab
           - const: allwinner,sun50i-a64

arch/arm64/boot/dts/allwinner/sun50i-a64-pinetab.dts

@@ -14,7 +14,7 @@
 #include <dt-bindings/pwm/pwm.h>
 
 / {
-	model = "PineTab";
+	model = "PineTab, Development Sample";
 	compatible = "pine64,pinetab", "allwinner,sun50i-a64";
 
 	aliases {