ide: it821x in pass-through mode segfaults in 2.6.26-stable

The driver of ITE8212 in pass-through mode (it8212.noraid=1 on cmndline)
attempts to use the field `.dma_host_set' of the struct ide_dma_ops in
`ide_config_drive_speed' which is set to NULL by default.

So give a value to all fields of the struct ide_dma_ops.

Signed-off-by: Dimitri Gorokhovik <dimitri.gorokhovik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>