dts: Break all dependencies of DTS on ext
dts: Break all dependencies of DTS on ext

If DTS does not depend on include paths determined in /ext then we can
move dts next to kconfig. Moving it next to kconfig means that DTS
CONFIG_ variables will be available at the same time as kconfig's
CONFIG_ variables which is the intended design and beneficial from a
usability perspective.

Signed-off-by: Sebastian Boe <edee888afd63e94916688495334700803eba20a0@nordicsemi.no>

Vudentz/zephyr,mbolivar/zephyr,explora26/zephyr,ldts/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,zephyriot/zephyr,explora26/zephyr,aceofall/zephyr-iotos,finikorg/zephyr,kraj/zephyr,ldts/zephyr,explora26/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,punitvara/zephyr,zephyriot/zephyr,punitvara/zephyr,finikorg/zephyr,ldts/zephyr,mbolivar/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,kraj/zephyr,mbolivar/zephyr,aceofall/zephyr-iotos,Vudentz/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,kraj/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,mbolivar/zephyr,aceofall/zephyr-iotos,aceofall/zephyr-iotos,explora26/zephyr,kraj/zephyr,finikorg/zephyr,mbolivar/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,zephyriot/zephyr,galak/zephyr,aceofall/zephyr-iotos,zephyriot/zephyr,nashif/zephyr,galak/zephyr,Vudentz/zephyr,ldts/zephyr,nashif/zephyr,kraj/zephyr,nashif/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,zephyriot/zephyr,punitvara/zephyr