spi: nuvoton,npcm-fiu: Change spi-nor@0 name to flash@0

The node name for flash memories has been standardized to "flash@...".
Fix the example in nuvoton,npcm-fiu.txt accordingly.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20221031222559.199509-1-j.neuschaefer@gmx.net


Signed-off-by: Mark Brown <broonie@kernel.org>