Add the device tree files for sama5d3xek board.
The dts files are copied from Linux-4.9, do the changes as below.
- add reg property for the pinctrl node.
- move the gpio nodes (pioA, pioB, pioC ...) as the pinctrl's
slibling nodes.
- add the "u-boot,dm-pre-reloc" property to determine which nodes
which are needed by SPL and by the board_init_f stage.
- fix the compile warning.
- add spi0 node aliases.
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
