drm/gma500: Add the missed drm_gem_object_put() in psb_user_framebuffer_create()

psb_user_framebuffer_create() misses to call drm_gem_object_put() in an
error path. Add the missed function call to fix it.
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210629115956.15160-1-jingxiangfeng@huawei.com

drivers/gpu/drm/gma500/framebuffer.c

@@ -352,6 +352,7 @@ static struct drm_framebuffer *psb_user_framebuffer_create
 			 const struct drm_mode_fb_cmd2 *cmd)
 {
 	struct drm_gem_object *obj;
+	struct drm_framebuffer *fb;
 
 	/*
 	 *	Find the GEM object and thus the gtt range object that is
@@ -362,7 +363,11 @@ static struct drm_framebuffer *psb_user_framebuffer_create
 		return ERR_PTR(-ENOENT);
 
 	/* Let the core code do all the work */
-	return psb_framebuffer_create(dev, cmd, obj);
+	fb = psb_framebuffer_create(dev, cmd, obj);
+	if (IS_ERR(fb))
+		drm_gem_object_put(obj);
+
+	return fb;
 }
 
 static int psbfb_probe(struct drm_fb_helper *fb_helper,