cmake: Convert module_init to function
cmake: Convert module_init to function

This is a housekeeping commit to move the upm_module_init
macro to a function.  The scope resolution of the function
call adds a bit more protection for the variables used inside
this macro/function.

Signed-off-by: Noel Eck <1e36ab6ededef40f3f16bdbc1b09eee72c5d08cf@intel.com>

malikabhi05/upm,whbruce/upm,stefan-andritoiu/upm,g-vidal/upm,sasmita/upm,nitirohilla/upm,whbruce/upm,intel-iot-devkit/upm,spitfire88/upm,malikabhi05/upm,nitirohilla/upm,sasmita/upm,nitirohilla/upm,Jon-ICS/upm,Propanu/upm,nitirohilla/upm,g-vidal/upm,spitfire88/upm,skiselev/upm,spitfire88/upm,jontrulson/upm,intel-iot-devkit/upm,Propanu/upm,spitfire88/upm,intel-iot-devkit/upm,whbruce/upm,jontrulson/upm,pylbert/upm,stefan-andritoiu/upm,g-vidal/upm,Jon-ICS/upm,malikabhi05/upm,nitirohilla/upm,jontrulson/upm,skiselev/upm,jontrulson/upm,intel-iot-devkit/upm,g-vidal/upm,jontrulson/upm,stefan-andritoiu/upm,pylbert/upm,Propanu/upm,pylbert/upm,Propanu/upm,g-vidal/upm,Propanu/upm,stefan-andritoiu/upm,malikabhi05/upm,skiselev/upm,skiselev/upm,g-vidal/upm,intel-iot-devkit/upm,stefan-andritoiu/upm,skiselev/upm,pylbert/upm,Propanu/upm,Jon-ICS/upm,malikabhi05/upm,sasmita/upm,sasmita/upm,intel-iot-devkit/upm,pylbert/upm,skiselev/upm,Jon-ICS/upm,whbruce/upm,whbruce/upm,pylbert/upm,spitfire88/upm,malikabhi05/upm,Jon-ICS/upm,sasmita/upm,stefan-andritoiu/upm