dt-bindings: reset: nuvoton,npcm-reset: Convert to yaml

Convert the device tree bindings for the Nuvoton NPCM reset controller
to YAML schema to allow participating in DT validation.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Avi Fishman <avifishman70@gmail.com>
Cc: Tomer Maimon <tmaimon77@gmail.com>
Cc: Tali Perry <tali.perry1@gmail.com>
Cc: Patrick Venture <venture@google.com>
Cc: Nancy Yuen <yuenn@google.com>
Cc: Benjamin Fair <benjaminfair@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220407154338.4190674-6-p.zabel@pengutronix.de