of: documentation: add bindings documentation for TS-4900

This adds the documentation for the TS-4900 by Technologic Systems.
Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/arm/technologic.txt

@@ -4,3 +4,9 @@ Technologic Systems Platforms Device Tree Bindings
 TS-4800 board
 Required root node properties:
 	- compatible = "technologic,imx51-ts4800", "fsl,imx51";
+
+TS-4900 is a System-on-Module based on the Freescale i.MX6 System-on-Chip.
+It can be mounted on a carrier board providing additional peripheral connectors.
+Required root node properties:
+	- compatible = "technologic,imx6dl-ts4900", "fsl,imx6dl"
+	- compatible = "technologic,imx6q-ts4900", "fsl,imx6q"