pata_radisys: fix checking of DMA state

Checking if DMA is enabled should be done via the
ata_dma_enabled helper function, since the init state
0xff indicates disabled.
Change based on code review, not tested due to lack of hardware.
Signed-off-by: NReimar Döffinger <Reimar.Doeffinger@gmx.de>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>

drivers/ata/pata_radisys.c

@@ -172,8 +172,8 @@ static unsigned int radisys_qc_issue(struct ata_queued_cmd *qc)
 
 	if (adev != ap->private_data) {
 		/* UDMA timing is not shared */
-		if (adev->dma_mode < XFER_UDMA_0) {
-			if (adev->dma_mode)
+		if (adev->dma_mode < XFER_UDMA_0 || !ata_dma_enabled(adev)) {
+			if (ata_dma_enabled(adev))
 				radisys_set_dmamode(ap, adev);
 			else if (adev->pio_mode)
 				radisys_set_piomode(ap, adev);