dt-bindings: MIPS: Require SoC compatible string after board string

All devicetree board files list a compatible string for the SoC after
the compatible string of the board.

Enhance the YAML format so that these SoC compatible strings appear
aside each supported Ingenic board.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/mips/ingenic/devices.yaml

@@ -20,16 +20,20 @@ properties:
       - description: Qi Hardware Ben NanoNote
         items:
           - const: qi,lb60
+          - const: ingenic,jz4740
 
       - description: Game Consoles Worldwide GCW Zero
         items:
           - const: gcw,zero
+          - const: ingenic,jz4770
 
       - description: MIPS Creator CI20
         items:
           - const: img,ci20
+          - const: ingenic,jz4780
 
       - description: YSH & ATIL General Board CU Neo
         items:
           - const: yna,cu1000-neo
+          - const: ingenic,x1000
 ...