zephyr/tests/bluetooth/init/pa_lna.overlay

/ {
	nrf_radio_fem: fem {
		compatible = "generic-fem-two-ctrl-pins";
		ctx-gpios = <&gpio0 26 0>;
		ctx-settle-time-us = <5>;
		crx-gpios = <&gpio0 27 0>;
		crx-settle-time-us = <5>;
	};
};

&radio {
	fem = <&nrf_radio_fem>;
};