wl12xx: enable/disable BET with AUTO_PS/ACTIVE

While the FW with dynamic PS controls BET when going to PSM and back
internally within the FW, there's still a need to enable it from the driver
at least once (so enable on every entry to AUTO_PS)
and disable it once we explicitly go back to STATION_ACTIVE_MODE.
BET isn't relevant for 5GHz

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/wl12xx/ps.c

@@ -181,6 +181,13 @@ int wl1271_ps_set_mode(struct wl1271 *wl, struct wl12xx_vif *wlvif,
 			return ret;
 
 		set_bit(WLVIF_FLAG_PSM, &wlvif->flags);
+
+		/* enable beacon early termination. Not relevant for 5GHz */
+		if (wlvif->band == IEEE80211_BAND_2GHZ) {
+			ret = wl1271_acx_bet_enable(wl, wlvif, true);
+			if (ret < 0)
+				return ret;
+		}
 		break;
 	case STATION_ACTIVE_MODE:
 		wl1271_debug(DEBUG_PSM, "leaving psm");