pdc202xx_old: add missing ->dma_base check

If ->dma_base is not set (== PCI BAR4 cannot be reserved) then DMA hooks
shouldn't be initialized or bad things will happen.
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/pci/pdc202xx_old.c

 /*
- *  linux/drivers/ide/pci/pdc202xx_old.c	Version 0.50	Mar 3, 2007
+ *  linux/drivers/ide/pci/pdc202xx_old.c	Version 0.51	Jul 27, 2007
  *
  *  Copyright (C) 1998-2002		Andre Hedrick <andre@linux-ide.org>
  *  Copyright (C) 2006-2007		MontaVista Software, Inc.
@@ -337,15 +337,18 @@ static void __devinit init_hwif_pdc202xx(ide_hwif_t *hwif)
 
 	hwif->speedproc = &pdc202xx_tune_chipset;
 
+	hwif->err_stops_fifo = 1;
+
 	hwif->drives[0].autotune = hwif->drives[1].autotune = 1;
 
+	if (hwif->dma_base == 0)
+		return;
+
 	hwif->ultra_mask = hwif->cds->udma_mask;
 	hwif->mwdma_mask = 0x07;
 	hwif->swdma_mask = 0x07;
 	hwif->atapi_dma = 1;
 
-	hwif->err_stops_fifo = 1;
-
 	hwif->ide_dma_check = &pdc202xx_config_drive_xfer_rate;
 	hwif->dma_lost_irq = &pdc202xx_dma_lost_irq;
 	hwif->dma_timeout = &pdc202xx_dma_timeout;