dt-bindings: mmc: fsl,esdhc: Add explicit reference to mmc-controller-common

Even though it is referenced by mmc/mmc-controller.yaml it still raises
the warning:
esdhc@1560000 (fsl,ls1021a-esdhc): Unevaluated properties are not allowed ('bus-width' was unexpected)

Adding an explicit reference fixes this.

Signed-off-by: Alexander Stein <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

Documentation/devicetree/bindings/mmc/fsl,esdhc.yaml

···
 
 allOf:
   - $ref: sdhci-common.yaml#
+  - $ref: mmc-controller-common.yaml#
 
 unevaluatedProperties: false