spi: dt-bindings: add nxp,lpc3220-spi.yaml

Add lpc3220 spi controller binding doc to fix below CHECK_DTBS warning:
  arch/arm/boot/dts/nxp/lpc/lpc3250-ea3250.dtb: /ahb/apb/spi@20088000: failed to match any schema with compatible: ['nxp,lpc3220-spi']

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250625215255.2640538-1-Frank.Li@nxp.com


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