spi: Add bindings for new Ingenic SoCs.

Add the SPI bindings for the JZ4775 SoC, the X1000 SoC,
and the X2000 SoC from Ingenic.

Signed-off-by: 周琰杰 (Zhou Yanjie) <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Paul Cercueil <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/spi/ingenic,spi.yaml

···
     oneOf:
       - enum:
           - ingenic,jz4750-spi
+          - ingenic,jz4775-spi
           - ingenic,jz4780-spi
+          - ingenic,x1000-spi
+          - ingenic,x2000-spi
       - items:
           - enum:
               - ingenic,jz4760-spi