ide: fix host drivers missing hwif->chipset initialization

ide_find_port() now depends on ->chipset being set for occupied ide_hwifs[]
slots so all host drivers have to initialize hwif->chipset properly.

This patch fixes a regression on hosts with > 1 port or with a single port
but no devices attached to it for an affected host drivers.

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