samples: sensor: Add sample to demonstrate NPCX ADC Comparator driver

Add sample code that demonstrate the usage for Nuvoton ADC Comparator
driver, this driver is available for NPCX microcontroller family,
this sample is supported on npcx9m6f_evb board.

Signed-off-by: Bernardo Perez Priego <bernardo.perez.priego@intel.com>