netfilter: nft_tunnel: restrict it to netdev family

stable inclusion
from stable-v5.10.140
commit 35519ce7bac9138b00126817c7ddb8f4ebdbc066
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I63FTT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35519ce7bac9138b00126817c7ddb8f4ebdbc066



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

[ Upstream commit 01e4092d ]

Only allow to use this expression from NFPROTO_NETDEV family.

Fixes: af308b94 ("netfilter: nf_tables: add tunnel support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>