ata: ahci_st: build fixes

* The config option for ahci_st driver was renamed from
  CONFIG_SATA_AHCI_ST to CONFIG_AHCI_ST but Makefile was
  not updated.  Fix it (also while at it move the ahci_st
  driver entry below ahci_imx and ahci_sunxi ones).

* Fix a few build issues in the ahci_st driver itself.

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
index 17191b9..e1aa544 100644
--- a/drivers/ata/ahci_st.c
+++ b/drivers/ata/ahci_st.c
@@ -87,7 +87,7 @@
 	return 0;
 }
 
-static int st_ahci_exit(struct device *dev)
+static void st_ahci_exit(struct device *dev)
 {
 	struct st_ahci_drv_data *drv_data = dev_get_drvdata(dev);
 	struct ahci_host_priv *hpriv = drv_data->hpriv;
@@ -96,12 +96,10 @@
 	if (drv_data->pwr) {
 		err = reset_control_assert(drv_data->pwr);
 		if (err)
-			dev_err(&pdev->dev, "unable to pwrdwn\n");
+			dev_err(dev, "unable to pwrdwn\n");
 	}
 
 	ahci_platform_disable_resources(hpriv);
-
-	return 0;
 }
 
 static int st_ahci_probe_resets(struct platform_device *pdev)
@@ -186,9 +184,9 @@
 	struct ahci_host_priv *hpriv = drv_data->hpriv;
 	int err;
 
-	ret = ahci_platform_suspend_host(dev);
-	if (ret)
-		return ret;
+	err = ahci_platform_suspend_host(dev);
+	if (err)
+		return err;
 
 	if (drv_data->pwr) {
 		err = reset_control_assert(drv_data->pwr);