drm/radeon: Implement radeon_pci_shutdown

Currently radeon devices are not properly shutdown during kexec. This
causes a varity of issues, e.g. dpm initialization failures.
Fix this by implementing a radeon_pci_shutdown function, that unloads
the driver cleanly.

Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 9902ac7..dfd4149 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -506,6 +506,15 @@
 #endif
 };
 
+
+static void
+radeon_pci_shutdown(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+
+	radeon_driver_unload_kms(dev);
+}
+
 static struct drm_driver kms_driver = {
 	.driver_features =
 	    DRIVER_USE_AGP |
@@ -575,6 +584,7 @@
 	.probe = radeon_pci_probe,
 	.remove = radeon_pci_remove,
 	.driver.pm = &radeon_pm_ops,
+	.shutdown = radeon_pci_shutdown,
 };
 
 static int __init radeon_init(void)