Add ->chipset field to ide_pci_device_t and use it in ide_hwif_configure()
to set hwif->chipset.  Convert cmd64x, cy82c693, rz1000 and trm290 host
drivers to use this new ability.

While at it define hwif_chipset_t as u8 to save some space in hw_regs_t,
ide_hwif_t and ide_pci_device_t instances.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>