drm/ingenic: Drop explicit drm_mode_config_cleanup call

Allows us to drop the drm_driver.release callback.

This is made possible by a preceeding patch which added a drmm_
cleanup action to drm_mode_config_init(), hence all we need to do to
ensure that drm_mode_config_cleanup() is run on final drm_device
cleanup is check the new error code for _init().

v2: Explain why this cleanup is possible (Laurent).

v3: Use drmm_mode_config_init() for more clarity (Sam, Thomas)
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Paul Cercueil <paul@crapouillou.net> (v2)
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-32-daniel.vetter@ffwll.ch

drivers/gpu/drm/ingenic/ingenic-drm.c

@@ -489,11 +489,6 @@ static irqreturn_t ingenic_drm_irq_handler(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
-static void ingenic_drm_release(struct drm_device *drm)
-{
-	drm_mode_config_cleanup(drm);
-}
-
 static int ingenic_drm_enable_vblank(struct drm_crtc *crtc)
 {
 	struct ingenic_drm *priv = drm_crtc_get_priv(crtc);
@@ -537,7 +532,6 @@ static struct drm_driver ingenic_drm_driver_data = {
 	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
 
 	.irq_handler		= ingenic_drm_irq_handler,
-	.release		= ingenic_drm_release,
 };
 
 static const struct drm_plane_funcs ingenic_drm_primary_plane_funcs = {
@@ -638,7 +632,10 @@ static int ingenic_drm_probe(struct platform_device *pdev)
 	}
 	drmm_add_final_kfree(drm, priv);
 
-	drm_mode_config_init(drm);
+	ret = drmm_mode_config_init(drm);
+	if (ret)
+		return ret;
+
 	drm->mode_config.min_width = 0;
 	drm->mode_config.min_height = 0;
 	drm->mode_config.max_width = soc_info->max_width;