ata: fix sparse warning in ata_piix.c

drivers/ata/ata_piix.c:1655:8: warning: symbol 'rc' shadows an earlier one
drivers/ata/ata_piix.c:1616:6: originally declared here

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 9c2515f..752e7d2 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -1652,7 +1652,7 @@
 		u8 tmp;
 		pci_read_config_byte(pdev, PIIX_SCC, &tmp);
 		if (tmp == PIIX_AHCI_DEVICE) {
-			int rc = piix_disable_ahci(pdev);
+			rc = piix_disable_ahci(pdev);
 			if (rc)
 				return rc;
 		}