pata_optidma: 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: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>

drivers/ata/pata_optidma.c

@@ -153,7 +153,7 @@ static void optidma_mode_setup(struct ata_port *ap, struct ata_device *adev, u8
 	if (pair) {
 		u8 pair_addr;
 		/* Hardware constraint */
-		if (pair->dma_mode)
+		if (ata_dma_enabled(pair))
 			pair_addr = 0;
 		else
 			pair_addr = addr_timing[pci_clock][pair->pio_mode - XFER_PIO_0];
@@ -301,7 +301,7 @@ static u8 optidma_make_bits43(struct ata_device *adev)
 	};
 	if (!ata_dev_enabled(adev))
 		return 0;
-	if (adev->dma_mode)
+	if (ata_dma_enabled(adev))
 		return adev->dma_mode - XFER_MW_DMA_0;
 	return bits43[adev->pio_mode - XFER_PIO_0];
 }