drm: Garbage collect drm_dev_fini

It has become empty. Given the few users I figured not much point
splitting this up.

v2: Rebase over i915 changes.

v3: Rebase over patch split fix.

Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-26-daniel.vetter@ffwll.ch
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index c6ae888..b778f36 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -262,9 +262,7 @@ struct drm_driver {
 	 * @release:
 	 *
 	 * Optional callback for destroying device data after the final
-	 * reference is released, i.e. the device is being destroyed. Drivers
-	 * using this callback are responsible for calling drm_dev_fini()
-	 * to finalize the device and then freeing the struct themselves.
+	 * reference is released, i.e. the device is being destroyed.
 	 */
 	void (*release) (struct drm_device *);
 
@@ -620,7 +618,6 @@ int drm_dev_init(struct drm_device *dev,
 int devm_drm_dev_init(struct device *parent,
 		      struct drm_device *dev,
 		      struct drm_driver *driver);
-void drm_dev_fini(struct drm_device *dev);
 
 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 				 struct device *parent);