ARM: dt: tegra{20,30}.dtsi: Rename "mc" to "memory-controller"

Use a more plain english name.
Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
[swarren: remove redundant unit address from tegra30.dtsi change]
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/boot/dts/tegra20.dtsi

@@ -164,7 +164,7 @@ pmc {
 		reg = <0x7000e400 0x400>;
 	};
 
-	mc {
+	memory-controller@0x7000f000 {
 		compatible = "nvidia,tegra20-mc";
 		reg = <0x7000f000 0x024
 		       0x7000f03c 0x3c4>;

arch/arm/boot/dts/tegra30.dtsi

@@ -167,7 +167,7 @@ pmc {
 		reg = <0x7000e400 0x400>;
 	};
 
-	mc {
+	memory-controller {
 		compatible = "nvidia,tegra30-mc";
 		reg = <0x7000f000 0x010
 		       0x7000f03c 0x1b4