scripts/dts: Remove redundant 'children' check in create_aliases()
scripts/dts: Remove redundant 'children' check in create_aliases()

All nodes have a 'children' key.

Also simplify and improve naming a bit.

Signed-off-by: Ulf Magnusson <01743f1c1deb1fe75271d62edb65757d98ac0bcb@nordicsemi.no>

nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,nashif/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,ldts/zephyr,nashif/zephyr,nashif/zephyr,ldts/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr