[nrf fromlist] dts: common: nordic: Add clock property for fast PWM120

Added hsfll120 clock for fast PWM120 nodes.

Upstream PR #: 80672

Signed-off-by: Michał Stasiak <[email protected]>

Author: mstasiaknordic

dts/common/nordic/nrf54h20.dtsi

@@ -622,6 +622,7 @@
 				reg = <0x8e4000 0x1000>;
 				status = "disabled";
 				interrupts = <228 NRF_DEFAULT_IRQ_PRIORITY>;
+				clocks = <&hsfll120>;
 				#pwm-cells = <3>;
 			};