dt-bindings: mmc: fsl-imx-esdhc: add i.MXRT compatible string

Add i.MXRT documentation for compatible string.

Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211125211443.1150135-11-Mr.Bossman075@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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

@@ -34,6 +34,7 @@ properties:
           - fsl,imx6ull-usdhc
           - fsl,imx7d-usdhc
           - fsl,imx7ulp-usdhc
+          - fsl,imxrt1050-usdhc
           - nxp,s32g2-usdhc
       - items:
           - enum: