spi: dt-bindings: fsl-dspi: Convert to yaml format

Convert dt-binding spi-fsl-dspi.txt to yaml format.
Use part Vladimir Oltean's work at of
https://lore.kernel.org/linux-spi/20221111224651.577729-1-vladimir.oltean@nxp.com/



Additional changes during convert:
- compatible string "fsl,ls1028a-dspi" can be followed by
fsl,ls1021a-v1.0-dspi.
- Change "dspi0@4002c000" to "spi@4002c000" in example.
- Reorder properties in example.
- Use GIC include in example.
- Deprecated fsl,spi-cs-sck-delay and fsl,spi-sck-cs-delay by use common SPI
property.
- Use compatible string 'jedec,spi-nor' in example.
- Split peripheral part to fsl,dspi-peripheral-props.yaml.
- Remove 'interrupts' and 'pinctrl' from required list.
- Update 'bus-num' description.
- Update 'spi-num-chipselects' description by add "cs-gpios don't count
against this number".
- Remove 'big-endian' description.

Co-developed-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Co-developed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20240624-ls_qspi-v4-2-3d1c6f5005bf@nxp.com


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