dt-bindings: clock: Correct mmc node name in i.MX35 binding

Nodename should be "mmc" instead of "esdhc" in i.MX35 clock binding
to avoid below build error:

Documentation/devicetree/bindings/clock/imx35-clock.example.dt.yaml:
esdhc@53fb4000: $nodename:0: 'esdhc@53fb4000' does not match '^mmc(@.*)?$'
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1592450578-30140-2-git-send-email-Anson.Huang@nxp.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/clock/imx35-clock.yaml

@@ -130,7 +130,7 @@ examples:
         #clock-cells = <1>;
     };
 
-    esdhc@53fb4000 {
+    mmc@53fb4000 {
         compatible = "fsl,imx35-esdhc";
         reg = <0x53fb4000 0x4000>;
         interrupts = <7>;