tcp: Factorise sk_family-independent comparison in inet_bind2_bucket_match(_addr_any).

[ Upstream commit c6d27706

 ]

This is a prep patch to make the following patches cleaner that touch
inet_bind2_bucket_match() and inet_bind2_bucket_match_addr_any().

Both functions have duplicated comparison for netns, port, and l3mdev.
Let's factorise them.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: aa99e5f8

 ("tcp: Fix bind() regression for v4-mapped-v6 wildcard address.")
Signed-off-by: Sasha Levin <sashal@kernel.org>