net: caif: fix memory leak in caif_device_notify

stable inclusion
from stable-v4.19.194
commit 3be863c11cab725add9fef4237ed4e232c3fc3bb
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I990A7
CVE: CVE-2021-47122

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3be863c11cab725add9fef4237ed4e232c3fc3bb



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

commit b53558a9 upstream.

In case of caif_enroll_dev() fail, allocated
link_support won't be assigned to the corresponding
structure. So simply free allocated pointer in case
of error

Fixes: 7c18d220 ("caif: Restructure how link caif link layer enroll")
Cc: stable@vger.kernel.org
Reported-and-tested-by:  <syzbot+7ec324747ce876a29db6@syzkaller.appspotmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Liu Jian <liujian56@huawei.com>