ARM: dts: exynos: Align L2 cache-controller nodename with dtschema

Fix dtschema warning message by changing nodename to 'cache-controller':

DT_SCHEMA_FILES=Documentation/devicetree/bindings/arm/l2c2x0.yaml
arch/arm/boot/dts/exynos4210-i9100.dt.yaml: l2-cache-controller@10502000:
$nodename:0: 'l2-cache-controller@10502000' does not match '
^(cache-controller|cpu)(@[0-9a-f,]+)*$'

Signed-off-by: Anand Moon <[e-mail]>
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

arch/arm/boot/dts/exynos4210.dtsi

···
 			label = "LCD1";
 		};
 
-		l2c: l2-cache-controller@10502000 {
+		l2c: cache-controller@10502000 {
 			compatible = "arm,pl310-cache";
 			reg = <0x10502000 0x1000>;
 			cache-unified;

arch/arm/boot/dts/exynos4412.dtsi

···
 			label = "ISP";
 		};
 
-		l2c: l2-cache-controller@10502000 {
+		l2c: cache-controller@10502000 {
 			compatible = "arm,pl310-cache";
 			reg = <0x10502000 0x1000>;
 			cache-unified;