libata: handle pci_enable_device() failure while resuming

Handle pci_enable_device() failure while resuming.  This patch kills
the "ignoring return value of 'pci_enable_device'" warning message and
propagates __must_check through ata_pci_device_do_resume().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index a03019c..89f3cf5 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6196,12 +6196,22 @@
 	}
 }
 
-void ata_pci_device_do_resume(struct pci_dev *pdev)
+int ata_pci_device_do_resume(struct pci_dev *pdev)
 {
+	int rc;
+
 	pci_set_power_state(pdev, PCI_D0);
 	pci_restore_state(pdev);
-	pci_enable_device(pdev);
+
+	rc = pci_enable_device(pdev);
+	if (rc) {
+		dev_printk(KERN_ERR, &pdev->dev,
+			   "failed to enable device after resume (%d)\n", rc);
+		return rc;
+	}
+
 	pci_set_master(pdev);
+	return 0;
 }
 
 int ata_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
@@ -6221,10 +6231,12 @@
 int ata_pci_device_resume(struct pci_dev *pdev)
 {
 	struct ata_host *host = dev_get_drvdata(&pdev->dev);
+	int rc;
 
-	ata_pci_device_do_resume(pdev);
-	ata_host_resume(host);
-	return 0;
+	rc = ata_pci_device_do_resume(pdev);
+	if (rc == 0)
+		ata_host_resume(host);
+	return rc;
 }
 #endif /* CONFIG_PCI */