ath9k: release allocated buffer if timed out

[ Upstream commit 728c1e2a05e4b5fc52fab3421dce772a806612a2 ]

In ath9k_wmi_cmd, the allocated network buffer needs to be released
if timeout happens. Otherwise memory will be leaked.

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>