qcacld-3.0: Release mutex before returning

Release remain_on_chan_ctx_lock mutex before returning to avoid thread
deadlock situation.
Change-Id: If5fb823ac2c042d34693abb8928dbc2159449a6e
CRs-Fixed: 2056611

core/hdd/src/wlan_hdd_p2p.c

@@ -1278,6 +1278,8 @@ __wlan_hdd_cfg80211_cancel_remain_on_channel(struct wiphy *wiphy,
 						OFF_CHANNEL_ACTION_TX;
 					pRemainChanCtx->cookie =
 						cfgState->action_cookie;
+					mutex_unlock(&cfgState->
+						remain_on_chan_ctx_lock);
 					return 0;
 				}
 			}