netfilter: nfnetlink_log: use proper helper for fetching physinif

[ Upstream commit c3f9fd54 ]

We don't use physindev in __build_packet_message except for getting
physinif from it. So let's switch to nf_bridge_get_physinif to get what
we want directly.

Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: 98748088 ("netfilter: bridge: replace physindev with physinif in nf_bridge_info")
Signed-off-by: Sasha Levin <sashal@kernel.org>