boards: arduino_due: Add make flash support

This patch automates flashing process for arduino_due board. Just make flash will able
to flash binary file on the board.

Bossa tool(http://www.shumatech.com/web/products/bossa

) manual flashing process is
automated through shell script and currently this binary is only available for
x86_64 architecture.

JIRA : ZEP-145

Change-Id: Ib7b525466239d0437e449c56827f8a9b3e5a96a1
Signed-off-by: Punit Vara <punit.vara@intel.com>