ath9k: MCC, print time elapsed between events

This is useful for MCC debugging and bug fixing.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index b42f4a9..acc21f6 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -981,6 +981,7 @@
 	struct ath_offchannel offchannel;
 	struct ath_chanctx *next_chan;
 	struct completion go_beacon;
+	struct timespec last_event_time;
 #endif
 
 	unsigned long driver_data;