arm: at91: Add support for DENX MA5D4 SoM and EVK

arm: at91: Add support for DENX MA5D4 SoM and EVK

Add support for DENX MA5D4 SoM and MA5D4EVK board, based on the
Atmel SAMA5D4 SoC. The SoM contains the SoC, eMMC, SPI NOR, SPI
CAN controllers and DRAM, the baseboard contains UART connectors,
ethernet port, microSD slot, LCD header, 2x CAN connector and a
lot of expansion headers.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andreas Bießmann <andreas.devel@googlemail.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Andreas Bießmann <andreas.devel@googlemail.com>