ARM: dts: at91: Add dts files for at91sam9m10g45ek

ARM: dts: at91: Add dts files for at91sam9m10g45ek

The device tree source files of at91sam9m10g45ek boards are copied
from the Linux v4.10, do the changes as below.
 - Add the reg property for the pinctrl node.
 - Move the gpio (pioA, pioB, pioC, pioD, pioE) nodes as the pinctrl's
   slibling nodes, instead of the child nodes.
 - Add the "u-boot,dm-pre-reloc" property to determine which nodes
   are used by the board_init_f stage.
 - Fix the compilation warnings.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>