sis5513: fail early for unsupported chipsets

* Factor out chipset family detection from init_chipset_sis5513()
  to sis_find_family().

* Use sis_find_family() in sis5513_init_one() to fail early if the
  chipset is unsupported.

* Keep a local copy sis5513_chipset in sis5513_init_one()
  and set .udma_mask according to chipset family.

* Remove no longer need ->ultra_mask setting from init_hwif_sis5513().

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