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

Fix dtschema validator warnings like:
l2-cache-controller@ac0000: $nodename:0:
'l2-cache-controller@ac0000' does not match '^(cache-controller|cpu)(@[0-9a-f,]+)*$'

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Jisheng Zhang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]'
Signed-off-by: Arnd Bergmann <[e-mail]>

arch/arm/boot/dts/berlin2.dtsi

···
 			status = "disabled";
 		};
 
-		l2: l2-cache-controller@ac0000 {
+		l2: cache-controller@ac0000 {
 			compatible = "marvell,tauros3-cache", "arm,pl310-cache";
 			reg = <0xac0000 0x1000>;
 			cache-unified;

arch/arm/boot/dts/berlin2cd.dtsi

···
 			status = "disabled";
 		};
 
-		l2: l2-cache-controller@ac0000 {
+		l2: cache-controller@ac0000 {
 			compatible = "arm,pl310-cache";
 			reg = <0xac0000 0x1000>;
 			cache-unified;

arch/arm/boot/dts/berlin2q.dtsi

···
 			status = "disabled";
 		};
 
-		l2: l2-cache-controller@ac0000 {
+		l2: cache-controller@ac0000 {
 			compatible = "arm,pl310-cache";
 			reg = <0xac0000 0x1000>;
 			cache-unified;