drm/stm: Drop explicit drm_mode_config_cleanup call

It's right above the drm_dev_put().

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().

Aside: Another driver with a bit much devm_kzalloc, which should
probably use drmm_kzalloc instead ...

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

v3: Use drmm_mode_config_init() for more clarity (Sam, Thomas)

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Philippe Cornu <philippe.cornu@st.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Yannick Fertre <yannick.fertre@st.com>
Cc: Philippe Cornu <philippe.cornu@st.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Vincent Abriou <vincent.abriou@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-39-daniel.vetter@ffwll.ch

drivers/gpu/drm/stm/drv.c

@@ -88,7 +88,9 @@ static int drv_load(struct drm_device *ddev)
 
 	ddev->dev_private = (void *)ldev;
 
-	drm_mode_config_init(ddev);
+	ret = drmm_mode_config_init(ddev);
+	if (ret)
+		return ret;
 
 	/*
 	 * set max width and height as default value.
@@ -103,7 +105,7 @@ static int drv_load(struct drm_device *ddev)
 
 	ret = ltdc_load(ddev);
 	if (ret)
-		goto err;
+		return ret;
 
 	drm_mode_config_reset(ddev);
 	drm_kms_helper_poll_init(ddev);
@@ -111,9 +113,6 @@ static int drv_load(struct drm_device *ddev)
 	platform_set_drvdata(pdev, ddev);
 
 	return 0;
-err:
-	drm_mode_config_cleanup(ddev);
-	return ret;
 }
 
 static void drv_unload(struct drm_device *ddev)
@@ -122,7 +121,6 @@ static void drv_unload(struct drm_device *ddev)
 
 	drm_kms_helper_poll_fini(ddev);
 	ltdc_unload(ddev);
-	drm_mode_config_cleanup(ddev);
 }
 
 static __maybe_unused int drv_suspend(struct device *dev)