ARM: dts: imx27: Change nand node name to nand-controller

Change i.MX27 nand node name from "nand" to "nand-controller" to
be compliant with yaml schema, it requires the nodename to be
"nand-controller".

Signed-off-by: Anson Huang <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx27.dtsi

···
 			};
 		};
 
-		nfc: nand@d8000000 {
+		nfc: nand-controller@d8000000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			compatible = "fsl,imx27-nand";