In npcx7 series, all of them support the Intel Enhanced Serial
Peripheral Interface (eSPI) Revision 1.0. This specification provides a
path for migrating host sub-devices via LPC to a lower pin count, higher
bandwidth bus. In addition to Host communication via the peripheral
channel, it provides virtual wires support, out-of-band communication,
and device mastering option over the Chipset SPI flash.
Becisdes introducing eSPI device in npcx7, this CL also includes:
1. Add eSPI device tree declarations.
2. Add npcx7-espi-vws-map.dtsi to present the relationship between eSPI
Virtual-Wire signals, eSPI registers, and wake-up input sources.
3. Zephyr eSPI api implementation.
4, Add OOB (Out of Band tunneled SMBus) support.
5. Add configuration files for eSPI test suites.
Signed-off-by: Mulin Chao <MLChao@nuvoton.com>