ide: introduce CONFIG_BLK_DEV_IDEDMA_SFF option

Introduce new option CONFIG_BLK_DEV_IDEDMA_SFF for non-PCI SFF-8038i compatible
bus mastering IDE controllers (which there are a few known), thus fixing a hack
made for Palmchip BK3710 controller...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Anton Salnikov <asalnikov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>