dt-binding: spi: npcm-pspi: Add npcm845 compatible

Add a compatible string for Nuvoton BMC NPCM845 PSPI.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20220722114136.251415-2-tmaimon77@gmail.com


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