dt-bindings: mmc: fsl-imx-esdhc: add imx7ulp compatible string

Add imx7ulp compatible string.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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

@@ -17,6 +17,7 @@ Required properties:
 	       "fsl,imx6sx-usdhc"
 	       "fsl,imx6ull-usdhc"
 	       "fsl,imx7d-usdhc"
+	       "fsl,imx7ulp-usdhc"
 	       "fsl,imx8qxp-usdhc"
 
 Optional properties: