qcacmn: Remove name indirection for ieee80211_get_channel()

Versions 4.11+ of the Linux kernel removed '__' from the beginning of
ieee80211_get_channel(). Migrate all calls from __ieee80211_get_channel
to ieee80211_get_channel instead.

Change-Id: I0548259beb59f0a3cb27fe6fee1dd9626cc624cc
CRs-Fixed: 2098795

src/wlan_cfg80211_p2p.c

@@ -284,8 +284,8 @@ static void wlan_p2p_event_callback(void *user_data,
 		goto fail;
 	}
 
-	chan = __ieee80211_get_channel(wdev->wiphy,
-			wlan_chan_to_freq(p2p_event->chan));
+	chan = ieee80211_get_channel(wdev->wiphy,
+				     wlan_chan_to_freq(p2p_event->chan));
 	if (p2p_event->roc_event == ROC_EVENT_READY_ON_CHAN) {
 		cfg80211_ready_on_channel(wdev,
 			p2p_event->cookie, chan,