Documentation: DT: Add entry for FSL LS2080A QDS and RDB boards

This patch adds a devicetree binding documentation for Freescale's
LS2080A QDS and RDB boards.
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/arm/fsl.txt

@@ -135,3 +135,11 @@ LS2080A ARMv8 based Simulator model
 Required root node properties:
     - compatible = "fsl,ls2080a-simu", "fsl,ls2080a";
 
+LS2080A ARMv8 based QDS Board
+Required root node properties:
+    - compatible = "fsl,ls2080a-qds", "fsl,ls2080a";
+
+LS2080A ARMv8 based RDB Board
+Required root node properties:
+    - compatible = "fsl,ls2080a-rdb", "fsl,ls2080a";
+