arm: dts: Move common arm includes into a dts system include

Introduce a system include so that board dts files are able to live in
any location and properly include the things they need.

Change-Id: Icd26433117a4ca9726aeb74eec9f72c6d9df617c
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

dts/arm/cc32xx_launchxl.dtsi

@@ -1,4 +1,4 @@
-#include "armv7-m.dtsi"
+#include <arm/armv7-m.dtsi>
 #include <inc/hw_memmap.h>
 #include <inc/hw_ints.h>
 

dts/arm/nxp_k6x.dtsi

@@ -1,4 +1,4 @@
-#include "armv7-m.dtsi"
+#include <arm/armv7-m.dtsi>
 
 / {
 	cpus {

dts/arm/nxp_kw41z.dtsi

@@ -1,4 +1,4 @@
-#include "armv6-m.dtsi"
+#include <arm/armv6-m.dtsi>
 
 / {
 	cpus {

dts/arm/stm32f103xb.dtsi

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include "armv7-m.dtsi"
+#include <arm/armv7-m.dtsi>
 
 / {
 	sram0: memory {

dts/arm/stm32l476.dtsi

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include "armv7-m.dtsi"
+#include <arm/armv7-m.dtsi>
 
 / {
 

dts/arm/v2m_beetle.dts

@@ -1,6 +1,6 @@
 /dts-v1/;
 
-#include "armv7-m.dtsi"
+#include <arm/armv7-m.dtsi>
 #include "arm/beetle/soc_irq.h"
 
 / {

scripts/Makefile.lib

@@ -156,6 +156,8 @@ dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 $(ZEPHYRINCLUDE)                                        \
 		 -I$(srctree)/arch/$(ARCH)/soc				 \
 		 -I$(srctree)/dts/common				 \
+		 -I$(srctree)/dts					 \
+		 -I$(srctree)/dts/$(ARCH)				 \
 		 -I$(srctree)/drivers/of/testcase-data                   \
 		 -undef -D__DTS__