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

Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml

@@ -49,6 +49,16 @@ properties:
       Delay in nanoseconds to be introduced by the controller after CS is
       asserted.
 
+  spi-cs-hold-delay-ns:
+    description:
+      Delay in nanoseconds to be introduced by the controller before CS is
+      de-asserted.
+
+  spi-cs-inactive-delay-ns:
+    description:
+      Delay in nanoseconds to be introduced by the controller after CS is
+      de-asserted.
+
   spi-rx-bus-width:
     description:
       Bus width to the SPI bus used for read transfers.