atiixp.c: remove unused code

A previous patch to atiixp.c was removed but some code has not been
cleaned. Now we remove these code sine they are no use any longer.

Signed-off-by: Conke Hu <conke.hu@amd.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>