via82cxxx: cleanup ->init_chipset method

* Move the boot message and via_clock setup from
  init_chipset_via82cxxx() to via_init_one().

* Set vdev->via_config in via_init_one() and cleanup
  init_chipset_via82cxxx() accordingly.

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