dt-bindings: mmc: imx-esdhc: Add imx93 compatible string

Add i.MX93 compatible string, it uses two compatible strings.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20220215081502.789067-1-peng.fan@oss.nxp.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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

@@ -47,6 +47,7 @@ properties:
           - const: fsl,imx7d-usdhc
       - items:
           - enum:
+              - fsl,imx93-usdhc
               - fsl,imx8ulp-usdhc
           - const: fsl,imx8mm-usdhc