pdc202xx_old: remove ->init_setup

* Split off pdc202ata4_fixup_irq() helper from init_setup_pdc202ata4().

* Merge init_setup_{pdc202ata4,pdc20265,pdc202xx}() into pdc202xx_init_one().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>