Documentation: DT: Add entry for DPAA2 console

This patch adds a devicetree binding documentation for
FSL's DPAA2 console.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Li Yang <leoyang.li@nxp.com>

Documentation/devicetree/bindings/misc/fsl,dpaa2-console.txt

@@ -0,0 +1,11 @@
+DPAA2 console support
+
+Required properties:
+
+    - compatible
+        Value type: <string>
+        Definition: Must be "fsl,dpaa2-console".
+    - reg
+        Value type: <prop-encoded-array>
+        Definition: A standard property.  Specifies the region where the MCFBA
+                    (MC firmware base address) register can be found.