ARM: dts: at91: add Overkiz KIZBOX3 board

Add a common DT include file for the Kizbox3 boards.
Add the devicetree for the Kizbox3 HS board.

Signed-off-by: Kévin RAYMOND <k.raymond@overkiz.com>
Signed-off-by: Mickael GARDET <m.gardet@overkiz.com>
Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Link: https://lore.kernel.org/r/20191011125022.16329-4-kamel.bouhara@bootlin.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>