Add gpio support for Nuvoton NPCX series. This CL includes:
1. Add GPIO device tree declarations.
2. Introduce wui_maps property in yaml file to present relationship
between Wake-Up
Input (WUI) and 8 IOs belong to the device.
3. Zephyr GPIO api implementation.
4. GPIO callback functions implementation with MIWU api functions.
5. Overlay file for gpio basic tests
Signed-off-by: Mulin Chao <MLChao@nuvoton.com>
