As done in the commit fa42d910 ("unix_bind(): take BSD and abstract
address cases into new helpers"), this patch moves BSD and abstract address
cases from unix_find_other() into unix_find_bsd() and unix_find_abstract().
Signed-off-by: NKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>