iwlegacy: Add a lock assertion in il4965_send_rxon_assoc()

The variables il->staging.filter_flags, rxon1->filter_flags and
rxon2->filter_flags need to be protected by the mutex lock il->mutex.
This patch adds a lock assertion of il->mutex to check whether
this lock is held.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intel/iwlegacy/4965.c

@@ -1297,6 +1297,8 @@ il4965_send_rxon_assoc(struct il_priv *il)
 	const struct il_rxon_cmd *rxon1 = &il->staging;
 	const struct il_rxon_cmd *rxon2 = &il->active;
 
+	lockdep_assert_held(&il->mutex);
+
 	if (rxon1->flags == rxon2->flags &&
 	    rxon1->filter_flags == rxon2->filter_flags &&
 	    rxon1->cck_basic_rates == rxon2->cck_basic_rates &&