mac80211: fix typo in action frame handling

This says chan_switch.action_code but really means
measurement.action_code, of course the actual offset in
the frame is the same, it's just harder to understand
this way.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mlme.c

@@ -2996,7 +2996,7 @@ static void ieee80211_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
 	case WLAN_CATEGORY_SPECTRUM_MGMT:
 		if (local->hw.conf.channel->band != IEEE80211_BAND_5GHZ)
 			break;
-		switch (mgmt->u.action.u.chan_switch.action_code) {
+		switch (mgmt->u.action.u.measurement.action_code) {
 		case WLAN_ACTION_SPCT_MSR_REQ:
 			if (len < (IEEE80211_MIN_ACTION_SIZE +
 				   sizeof(mgmt->u.action.u.measurement)))