ide: add "hdx=nodma" kernel parameter

* Add "hdx=nodma" option allowing user to disallow DMA for a given device.

* Obsolete "ide=nodma" option.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>