ksmbd: fix possible memory leak in smb2_lock()

argv needs to be free when setup_async_work fails or when the current
process is woken up.

Fixes: e2f34481 ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>