ide: cleanup ide_set_dma()

* ->dma_off_quietly is always called before ide_set_dma()
  so the call can be moved inside ide_set_dma().

* ide_dma_check() doesn't touch hardware so ->dma_off_quietly
  call for 'rc == -1' case is redundant, remove it.

* '0' and '-1' are the only values returned by ide_dma_check()
  so remove dead code for other cases.

There should be no functionality changes caused by this patch.

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

drivers/ide/ide.c

@@ -851,7 +851,6 @@ int set_using_dma(ide_drive_t *drive, int arg)
 	err = 0;
 
 	if (arg) {
-		hwif->dma_off_quietly(drive);
 		if (ide_set_dma(drive))
 			err = -EIO;
 	} else