ARM: tegra: Rename EMC on Tegra124

Rename the EMC node to external-memory-controller according to device
tree best practices.
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra124-apalis-emc.dtsi

@@ -84,7 +84,7 @@ timing-924000000 {
 		};
 	};
 
-	emc@7001b000 {
+	external-memory-controller@7001b000 {
 		emc-timings-1 {
 			nvidia,ram-code = <1>;
 

arch/arm/boot/dts/tegra124-jetson-tk1-emc.dtsi

@@ -79,7 +79,7 @@ timing-924000000 {
 		};
 	};
 
-	emc@7001b000 {
+	external-memory-controller@7001b000 {
 		emc-timings-3 {
 			nvidia,ram-code = <3>;
 

arch/arm/boot/dts/tegra124-nyan-big-emc.dtsi

@@ -219,7 +219,7 @@ timing-792000000 {
 		};
 	};
 
-	emc@7001b000 {
+	external-memory-controller@7001b000 {
 		emc-timings-1 {
 			nvidia,ram-code = <1>;
 

arch/arm/boot/dts/tegra124-nyan-blaze-emc.dtsi

@@ -68,7 +68,7 @@ timing-792000000 {
 		};
 	};
 
-	emc@7001b000 {
+	external-memory-controller@7001b000 {
 		emc-timings-1 {
 			nvidia,ram-code = <1>;
 

arch/arm/boot/dts/tegra124.dtsi

@@ -622,7 +622,7 @@ mc: memory-controller@70019000 {
 		#iommu-cells = <1>;
 	};
 
-	emc: emc@7001b000 {
+	emc: external-memory-controller@7001b000 {
 		compatible = "nvidia,tegra124-emc";
 		reg = <0x0 0x7001b000 0x0 0x1000>;
 		clocks = <&tegra_car TEGRA124_CLK_EMC>;