ide: fix IDE_DFLAG_NO_IO_32BIT handling

* IDE_DFLAG_NO_IO_32BIT may be set by cmd640's ->init_dev method
  so don't clear it in ide_port_tune_devices() (+ no need to do it).

* Move IDE_DFLAG_NO_IO_32BIT handling to ide_port_init_devices().

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