drm/gma500: Disable PCI device during shutdown

Use managed disablement of PCI devices via pcim_device_enable().
Disables the PCI device and simplifies error rollback in probe
function.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Patrik Jakobsson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/gma500/psb_drv.c

···
 	struct drm_device *dev;
 	int ret;
 
-	ret = pci_enable_device(pdev);
+	ret = pcim_enable_device(pdev);
 	if (ret)
 		return ret;
 
 	dev = drm_dev_alloc(&driver, &pdev->dev);
-	if (IS_ERR(dev)) {
-		ret = PTR_ERR(dev);
-		goto err_pci_disable_device;
-	}
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 
 	pci_set_drvdata(pdev, dev);
 
···
 	psb_driver_unload(dev);
 err_drm_dev_put:
 	drm_dev_put(dev);
-err_pci_disable_device:
-	pci_disable_device(pdev);
 	return ret;
 }