drm/radeon: Fix EEH during kexec

During kexec some adapters hit an EEH since they are not properly
shut down in the radeon_pci_shutdown() function. Adding
radeon_suspend_kms() fixes this issue.
Enabled only on PPC because this patch causes issues on some other
boards.
Signed-off-by: Kyle Mahlkuch <kmahlkuc@linux.vnet.ibm.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_drv.c

@@ -379,11 +379,25 @@ radeon_pci_remove(struct pci_dev *pdev)
 static void
 radeon_pci_shutdown(struct pci_dev *pdev)
 {
+#ifdef CONFIG_PPC64
+	struct drm_device *ddev = pci_get_drvdata(pdev);
+#endif
+
 	/* if we are running in a VM, make sure the device
 	 * torn down properly on reboot/shutdown
 	 */
 	if (radeon_device_is_virtual())
 		radeon_pci_remove(pdev);
+
+#ifdef CONFIG_PPC64
+	/* Some adapters need to be suspended before a
+	 * shutdown occurs in order to prevent an error
+	 * during kexec.
+	 * Make this power specific becauase it breaks
+	 * some non-power boards.
+	 */
+	radeon_suspend_kms(ddev, true, true, false);
+#endif
 }
 
 static int radeon_pmops_suspend(struct device *dev)