Char: merge ip2main and ip2base

It's pretty useless to have one setup() function separated along with
module_init() which only calls a function from ip2main anyway. Get rid
of ip2base.

Remove also checks of always-true now.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>