ide: use ide_destroy_dmatable() instead of pci_unmap_sg() (take 2)

Use ide_destroy_dmatable() in:
* ide-dma.c::ide_build_dmatable()
* sgiioc4.c::sgiioc4_build_dma_table()
* pmac.c::pmac_ide_{build,destroy}_dmatable()

There should be no functionality changes caused by this patch.

v2:
* pmac.c build fix from Andrew Morton.

Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/sgiioc4.c b/drivers/ide/pci/sgiioc4.c
index 9e0be7d..b60a5e8 100644
--- a/drivers/ide/pci/sgiioc4.c
+++ b/drivers/ide/pci/sgiioc4.c
@@ -517,8 +517,7 @@
 	}
 
 use_pio_instead:
-	pci_unmap_sg(hwif->pci_dev, hwif->sg_table, hwif->sg_nents,
-		     hwif->sg_dma_direction);
+	ide_destroy_dmatable(drive);
 
 	return 0;		/* revert to PIO for this request */
 }