drm/fb-helper: Automatically clean up fb_info

Noticed that everyone duplicates the same logic here and we could safe
a few lines per driver. Yay for lots of drivers to make such tiny
refactors worth-while!

v2: Forgot to git add everything :(

v3: Actually remove release_fbi (Sean, Emil, Chris) ...

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170207161603.17611-1-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
index 5d0ffab..4ad4acd 100644
--- a/drivers/gpu/drm/ast/ast_fb.c
+++ b/drivers/gpu/drm/ast/ast_fb.c
@@ -215,13 +215,13 @@
 	info = drm_fb_helper_alloc_fbi(helper);
 	if (IS_ERR(info)) {
 		ret = PTR_ERR(info);
-		goto err_free_vram;
+		goto out;
 	}
 	info->par = afbdev;
 
 	ret = ast_framebuffer_init(dev, &afbdev->afb, &mode_cmd, gobj);
 	if (ret)
-		goto err_release_fbi;
+		goto out;
 
 	afbdev->sysram = sysram;
 	afbdev->size = size;
@@ -250,9 +250,7 @@
 
 	return 0;
 
-err_release_fbi:
-	drm_fb_helper_release_fbi(helper);
-err_free_vram:
+out:
 	vfree(sysram);
 	return ret;
 }
@@ -287,7 +285,6 @@
 	struct ast_framebuffer *afb = &afbdev->afb;
 
 	drm_fb_helper_unregister_fbi(&afbdev->helper);
-	drm_fb_helper_release_fbi(&afbdev->helper);
 
 	if (afb->obj) {
 		drm_gem_object_unreference_unlocked(afb->obj);