ARM: berlin: dts: add the cpufreq-dt bindings on the BG2Q

The BG2Q uses cpugreq-dt. Add the corresponding bindings. The operating
points can be updated by the bootloader.
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

arch/arm/boot/dts/berlin2q.dtsi

@@ -58,6 +58,17 @@ cpu@0 {
 			device_type = "cpu";
 			next-level-cache = <&l2>;
 			reg = <0>;
+
+			clocks = <&chip_clk CLKID_CPU>;
+			clock-latency = <100000>;
+			/* Can be modified by the bootloader */
+			operating-points = <
+				/* kHz    uV */
+				1200000 1200000
+				1000000 1200000
+				800000  1200000
+				600000  1200000
+			>;
 		};
 
 		cpu@1 {