arm64: zynqmp: Add note about si5328 interrupt

Add comment about irq present on the board connected to PL.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/dts/zynqmp-zcu102-revA.dts

@@ -485,6 +485,11 @@ drivers/hwmon/pmbus/Makefile:11:obj-$(CONFIG_SENSORS_MAX20751)  += max20751.o
 			si5328: clock-generator4@69 {/* SI5328 - u20 */
 				compatible = "silabs,si5328";
 				reg = <0x69>;
+				/*
+				 * Chip has interrupt present connected to PL
+				 * interrupt-parent = <&>;
+				 * interrupts = <>;
+				 */
 			};
 		};
 		/* 5 - 7 unconnected */