dt-bindings: omap: Add Motorola mapphone mz609 and mz617 tablets

Let's add compatibles for some xyboard tablets, these are similar to
the mapphone devices already listed but with different peripherals.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

Documentation/devicetree/bindings/arm/ti/omap.yaml

@@ -134,6 +134,8 @@ properties:
               - amazon,omap4-kc1        # Amazon Kindle Fire (first generation)
               - motorola,droid4         # Motorola Droid 4 XT894
               - motorola,droid-bionic   # Motorola Droid Bionic XT875
+              - motorola,xyboard-mz609
+              - motorola,xyboard-mz617
               - ti,omap4-panda
               - ti,omap4-sdp
           - const: ti,omap4430