drm/cma: add debugfs helpers

Add helper to display fb's which can be used directly in drm_info_list:

static struct drm_info_list foo_debugfs_list[] = {
		...
		{ "fb",   drm_fb_cma_debugfs_show, 0 },
};

to display information about CMA fb objects, as well as a
drm_gem_cma_describe() which can be used if the driver bothers to keep
a list of CMA GEM objects.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/include/drm/drm_fb_cma_helper.h b/include/drm/drm_fb_cma_helper.h
index 76c7098..4a3fc24 100644
--- a/include/drm/drm_fb_cma_helper.h
+++ b/include/drm/drm_fb_cma_helper.h
@@ -23,5 +23,10 @@
 struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
 	unsigned int plane);
 
+#ifdef CONFIG_DEBUG_FS
+void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m);
+int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg);
+#endif
+
 #endif