ath9k: Fix channel context events

Check if channel context usage is enabled before
calling ath_chanctx_event() from various parts of the
driver. Also, make sure that ath_chanctx_event() is
compiled only when CONFIG_ATH9K_CHANNEL_CONTEXT is
enabled.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 704fcbc..2819866 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -2632,8 +2632,11 @@
 			sc->beacon.tx_processed = true;
 			sc->beacon.tx_last = !(ts.ts_status & ATH9K_TXERR_MASK);
 
-			ath_chanctx_event(sc, NULL,
-					  ATH_CHANCTX_EVENT_BEACON_SENT);
+			if (ath9k_is_chanctx_enabled()) {
+				ath_chanctx_event(sc, NULL,
+						  ATH_CHANCTX_EVENT_BEACON_SENT);
+			}
+
 			ath9k_csa_update(sc);
 			continue;
 		}