boards: arm: arduino_due: Added doc. image for the Arduino Due.

Signed-off-by: Justin Watson <[email protected]>

Author: fallrisk

boards/arm/arduino_due/doc/board.rst

@@ -23,7 +23,10 @@ the processor.
 .. note::
    This configuration is not supported by Arduino.
 
-
+.. image:: img/arduino_due.png
+     :width: 500px
+     :align: center
+     :alt: Arduino Due
 
 Hardware
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