cifs: fix wrong release in sess_alloc_buffer() failed path

stable inclusion
from linux-4.19.207
commit 1c409595b46bc405e9d4761d449d9307e009fc6f

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

[ Upstream commit d72c7419 ]

smb_buf is allocated by small_smb_init_no_tc(), and buf type is
CIFS_SMALL_BUFFER, so we should use cifs_small_buf_release() to
release it in failed path.

Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>