mwifiex: fix missing destroy_workqueue() on error in mwifiex_add_virtual_intf()

Add the missing destroy_workqueue() before return from
mwifiex_add_virtual_intf() in the error handling case.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/cfg80211.c

@@ -3022,6 +3022,8 @@ struct wireless_dev *mwifiex_add_virtual_intf(struct wiphy *wiphy,
 		priv->netdev = NULL;
 		memset(&priv->wdev, 0, sizeof(priv->wdev));
 		priv->wdev.iftype = NL80211_IFTYPE_UNSPECIFIED;
+		destroy_workqueue(priv->dfs_cac_workqueue);
+		priv->dfs_cac_workqueue = NULL;
 		return ERR_PTR(-ENOMEM);
 	}