dt-bindings: arm: Document Actions Semi S500

The Actions Semi S500 is a quad-core ARM Cortex-A9 SoC.
The LeMaker Guitar is an SODIMM-format module with that SoC.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>

Documentation/devicetree/bindings/arm/actions.txt

@@ -0,0 +1,24 @@
+Actions Semi platforms device tree bindings
+-------------------------------------------
+
+
+S500 SoC
+========
+
+Required root node properties:
+
+ - compatible :  must contain "actions,s500"
+
+
+Modules:
+
+Root node property compatible must contain, depending on module:
+
+ - LeMaker Guitar: "lemaker,guitar"
+
+
+Boards:
+
+Root node property compatible must contain, depending on board:
+
+ - LeMaker Guitar Base Board rev. B: "lemaker,guitar-bb-rev-b", "lemaker,guitar"