dt-bindings: mmc: fsl-imx-esdhc: add pinctrl bindings

Add pinctrl bindings for fsl-imx-esdhc yaml

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1614222604-27066-2-git-send-email-peng.fan@oss.nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.yaml

@@ -103,6 +103,15 @@ properties:
       Only eMMC HS400 mode need to take care of this property.
     default: 0
 
+  pinctrl-names:
+    minItems: 1
+    maxItems: 4
+    items:
+      - const: default
+      - const: state_100mhz
+      - const: state_200mhz
+      - const: sleep
+
 required:
   - compatible
   - reg