spi: dt-bindings: Move 'rx-sample-delay-ns' to spi-peripheral-props.yaml

SPI bus per device properties must be defined in spi-peripheral-props.yaml
for unevaluatedProperties checks to work correctly on device nodes.

This has the side effect of promoting 'rx-sample-delay-ns' to be a
common property, but functionally it's no different if it was defined in
a Synopsys specific schema file.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220525210053.2488756-1-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>