We can create a simple clock to know if it is loaded:

/dts-v1/;
/plugin/;

/ {
	compatible = "allwinner,d1-nezha\0allwinner,sun20i-d1";

	fragment@0 {
		target-path = "/";
		__overlay__ {
            /* External crystal oscillator on the board */
			can0_osc_fixed: can0_osc_fixed {
				compatible = "fixed-clock";
				#clock-cells = <0>;
				clock-frequency  = <8000000>;
                phandle = <0x81>;    // Arbitrary number
			};
		};
	};
};