samples: drivers: spi_flash: add support for the NPCX EVB

This commit adds the support to run the SPI NOR sample code on the
npcx7m6fb_evb and npcx9m6f_evb boards.

Signed-off-by: Jun Lin <CHLin56@nuvoton.com>
Change-Id: I780c5dfcf53f3ac537da946673fc03f5ee24e90c
3 files changed