west: zcmake.py: support UNINITIALIZED type if CMakeCache.txt file
west: zcmake.py: support UNINITIALIZED type if CMakeCache.txt file

A variable set by the user with `-DVAR=<val>` will be given the type
UNINITIALIZED.

This results in the variable not being read into the cmake_cache.

Support reading of CMake cache variables of type UNINITIALIZED.

Signed-off-by: Torsten Rasmussen <a7c5b1d5a1f41fce6edfa3f7c2392ae0c59deafe@nordicsemi.no>

galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr