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

Fix dtschema validator warnings like:
    l2-cache-controller@c00000: $nodename:0:
        'l2-cache-controller@c00000' does not match '^(cache-controller|cpu)(@[0-9a-f,]+)*$'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Jun Nie <jun.nie@linaro.org>

arch/arm/boot/dts/zx296702.dtsi

@@ -58,7 +58,7 @@ global_timer: timer@8000200 {
 			clocks = <&topclk ZX296702_A9_PERIPHCLK>;
 		};
 
-		l2cc: l2-cache-controller@c00000 {
+		l2cc: cache-controller@c00000 {
 			compatible = "arm,pl310-cache";
 			reg = <0x00c00000 0x1000>;
 			cache-unified;