ath9k: release allocated buffer if timed out

mainline inclusion
from mainline-v5.4-rc1
commit 728c1e2a05e4b5fc52fab3421dce772a806612a2
category: bugfix
bugzilla: 13690
CVE: CVE-2019-19074

-------------------------------------------------

In ath9k_wmi_cmd, the allocated network buffer needs to be released
if timeout happens. Otherwise memory will be leaked.
Signed-off-by: NNavid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/wireless/ath/ath9k/wmi.c

@@ -336,6 +336,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 		ath_dbg(common, WMI, "Timeout waiting for WMI command: %s\n",
 			wmi_cmd_to_name(cmd_id));
 		mutex_unlock(&wmi->op_mutex);
+		kfree_skb(skb);
 		return -ETIMEDOUT;
 	}