drm/qxl: Use drmm_add_final_kfree

With this we can drop the final kfree from the release function.
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: spice-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-8-daniel.vetter@ffwll.ch

drivers/gpu/drm/qxl/qxl_drv.c

@@ -144,8 +144,6 @@ static void qxl_drm_release(struct drm_device *dev)
 	 */
 	qxl_modeset_fini(qdev);
 	qxl_device_fini(qdev);
-	dev->dev_private = NULL;
-	kfree(qdev);
 }
 
 static void

drivers/gpu/drm/qxl/qxl_kms.c

@@ -27,6 +27,7 @@
 #include <linux/pci.h>
 
 #include <drm/drm_drv.h>
+#include <drm/drm_managed.h>
 #include <drm/drm_probe_helper.h>
 
 #include "qxl_drv.h"
@@ -121,6 +122,7 @@ int qxl_device_init(struct qxl_device *qdev,
 	qdev->ddev.pdev = pdev;
 	pci_set_drvdata(pdev, &qdev->ddev);
 	qdev->ddev.dev_private = qdev;
+	drmm_add_final_kfree(&qdev->ddev, qdev);
 
 	mutex_init(&qdev->gem.mutex);
 	mutex_init(&qdev->update_area_mutex);