netfilter: ebtables: fix memory leak when blob is malformed

stable inclusion
from stable-v5.10.146
commit ebd97dbe3c55d68346b9c5fb00634a7f5b10bbee
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0VX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ebd97dbe3c55d68346b9c5fb00634a7f5b10bbee



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[ Upstream commit 62ce44c4 ]

The bug fix was incomplete, it "replaced" crash with a memory leak.
The old code had an assignment to "ret" embedded into the conditional,
restore this.

Fixes: 7997eff8 ("netfilter: ebtables: reject blobs that don't provide all entry points")
Reported-and-tested-by:  <syzbot+a24c5252f3e3ab733464@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>