This patch removes unix_mkname() and postpones calculating a hash to
unix_bind_abstract().  Some BSD stuffs still remain in unix_bind()
though, the next patch packs them into unix_bind_bsd().
Signed-off-by: NKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>