ide: move ide_map_sg() call out of ->dma_setup method (take 2)

Move ide_map_sg() call from ->dma_setup implementations and
ide_destroy_dmatable() one from *_build_dmatable() to ide_dma_prepare().

There should be no functional changes caused by this patch.

Sergei:
Removed 'use_pio_instead' labels and replaced 'goto' with 'return 0' --
that required no changes to the follow-up patches...

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/scc_pata.c b/drivers/ide/scc_pata.c
index 693536e..2cdf51d 100644
--- a/drivers/ide/scc_pata.c
+++ b/drivers/ide/scc_pata.c
@@ -321,10 +321,8 @@
 	u8 dma_stat;
 
 	/* fall back to pio! */
-	if (ide_build_dmatable(drive, cmd) == 0) {
-		ide_map_sg(drive, cmd);
+	if (ide_build_dmatable(drive, cmd) == 0)
 		return 1;
-	}
 
 	/* PRD table */
 	out_be32((void __iomem *)(hwif->dma_base + 8), hwif->dmatable_dma);