netfilter: nf_tables_offload: Check for the NETDEV_UNREGISTER event

netfilter: nf_tables_offload: Check for the NETDEV_UNREGISTER event

[ Upstream commit d1f4c966475c6dd2545c6625022cb24e878bee11 ]

Check for the NETDEV_UNREGISTER event from the nft_offload_netdev_event
function, which is the event that actually triggers the clean up.

Fixes: 06d392cbe3db ("netfilter: nf_tables_offload: remove rules when the device unregisters")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>