spi: dt-bindings: snps,dw-apb-ssi: Merge duplicate compatible entry

Microsemi Ocelot/Jaguar2, Renesas RZ/N1 and T-HEAD TH1520
SoC-specific compatibles, which eventually fallback to the
generic DW ssi compatible, it's better to combine them in single entry

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Zixian Zeng <sycamoremoon376@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250425-sfg-spi-v6-1-2dbe7bb46013@gmail.com


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