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

Fix dtschema validator warnings like:
    l2-cache-controller@20100000: $nodename:0:
        'l2-cache-controller@20100000' does not match '^(cache-controller|cpu)(@[0-9a-f,]+)*$'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Mans Rullgard <mans@mansr.com>

arch/arm/boot/dts/tango4-common.dtsi

@@ -51,7 +51,7 @@ gic: interrupt-controller@1000 {
 		};
 	};
 
-	l2cc: l2-cache-controller@20100000 {
+	l2cc: cache-controller@20100000 {
 		compatible = "arm,pl310-cache";
 		reg = <0x20100000 0x1000>;
 		cache-level = <2>;