netfilter: nft_compat: reject unused compat flag

stable inclusion
from stable-v4.19.307
commit 56fb2bf4ab8c91a2e078553497b6c5b2f1dac699
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I970CO


CVE: NA

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

[ Upstream commit 292781c3c5485ce33bd22b2ef1b2bed709b4d672 ]

Flag (1 << 0) is ignored is set, never used, reject it it with EINVAL
instead.

Fixes: 0ca743a5 ("netfilter: nf_tables: add compatibility layer for x_tables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>