spi: dt-bindings: Add hold/inactive CS delay peripheral properties

These two properties complete the bindings for the Linux spi_device cs
model, which includes cs_setup, cs_hold and cs_inactive delay values.

Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230113102309.18308-3-marcan@marcan.st


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