scripts/extract_dts_includes: extract_reg_prop handle cells being 0
scripts/extract_dts_includes: extract_reg_prop handle cells being 0

Its possible that #size-cells is 0 (ie i2c bus).  So we should handle
either #address-cells or #size-cells being 0 in extract_reg_prop.  This
means that the reg property in reduced map will end up being an integer,
so we need to convert it to a list with one element.  We also need to
not output any address-cell or size-cell related info if the respective
cell is 0.

Signed-off-by: Kumar Gala <a5e5248af4cd4f0ed8c515f61d40a6e2db46a66e@linaro.org>

punitvara/zephyr,fbsder/zephyr,holtmann/zephyr,holtmann/zephyr,zephyrproject-rtos/zephyr,aceofall/zephyr-iotos,GiulianoFranchetto/zephyr,Vudentz/zephyr,aceofall/zephyr-iotos,ldts/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,holtmann/zephyr,ldts/zephyr,explora26/zephyr,rsalveti/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,Vudentz/zephyr,galak/zephyr,rsalveti/zephyr,Vudentz/zephyr,galak/zephyr,punitvara/zephyr,runchip/zephyr-cc3220,ldts/zephyr,finikorg/zephyr,runchip/zephyr-cc3220,zephyriot/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,runchip/zephyr-cc3220,fbsder/zephyr,Vudentz/zephyr,aceofall/zephyr-iotos,holtmann/zephyr,rsalveti/zephyr,GiulianoFranchetto/zephyr,mbolivar/zephyr,galak/zephyr,punitvara/zephyr,rsalveti/zephyr,rsalveti/zephyr,punitvara/zephyr,finikorg/zephyr,kraj/zephyr,holtmann/zephyr,Vudentz/zephyr,Vudentz/zephyr,kraj/zephyr,zephyriot/zephyr,ldts/zephyr,punitvara/zephyr,aceofall/zephyr-iotos,mbolivar/zephyr,aceofall/zephyr-iotos,finikorg/zephyr,explora26/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,fbsder/zephyr,nashif/zephyr,explora26/zephyr,finikorg/zephyr,fbsder/zephyr,mbolivar/zephyr,zephyriot/zephyr,runchip/zephyr-cc3220,explora26/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,fbsder/zephyr,kraj/zephyr,runchip/zephyr-cc3220,ldts/zephyr,zephyriot/zephyr