ARM: at91: dt: add dts files for sama5d3xek board

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>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index a2c0717..e7ccb53 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -347,6 +347,14 @@
 dtb-$(CONFIG_TARGET_SAMA5D2_XPLAINED) += \
 	at91-sama5d2_xplained.dtb
 
+dtb-$(CONFIG_TARGET_SAMA5D3XEK) += \
+	sama5d31ek.dtb \
+	sama5d33ek.dtb \
+	sama5d34ek.dtb \
+	sama5d35ek.dtb \
+	sama5d36ek.dtb \
+	sama5d36ek_cmp.dtb
+
 dtb-$(CONFIG_ARCH_BCM283X) += \
 	bcm2835-rpi-a-plus.dtb \
 	bcm2835-rpi-a.dtb \