sgiioc4: add ide_toggle_bounce() calls

Add ide_toggle_bounce() call to ->ide_dma_on/->dma_off_quietly
methods so they match generic __ide_dma_on()/ide_dma_off_quietly().

Tested on Altix by Jeremy.

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