wifi: Add units to listen interval

Listen interval as per 802.11 has units as "beacon intervals" i.e., 1
means 1 beacon interval duration (or short beacon interval duration if
short beacon is enabled).

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>
diff --git a/include/zephyr/net/wifi.h b/include/zephyr/net/wifi.h
index e3a1ed2..c64ee6a 100644
--- a/include/zephyr/net/wifi.h
+++ b/include/zephyr/net/wifi.h
@@ -547,7 +547,7 @@
 enum wifi_ps_param_type {
 	/** Power save state. */
 	WIFI_PS_PARAM_STATE,
-	/** Power save listen interval. */
+	/** Power save listen interval (units: (short) beacon intervals). */
 	WIFI_PS_PARAM_LISTEN_INTERVAL,
 	/** Power save wakeup mode. */
 	WIFI_PS_PARAM_WAKEUP_MODE,