board: laird: add WB50N CPU module

This board is based on the Atmel sama5d3 eval boards.
Supporting the following features:
 - Boot from NAND Flash
 - Ethernet
 - FIT
 - SPL

Signed-off-by: Ben Whitten <ben.whitten@lairdtech.com>
Signed-off-by: Dan Kephart <dan.kephart@lairdtech.com>
7 files changed