drm/fb-cma-helper: Hook up to DocBook and fix some docs

Hook up fb_cma_helper to DocBook. Remove mention of
CONFIG_FB_DEFERRED_IO in the docs, which was forgotten in the latest
version of the deferred_io patch.
Use & when referencing drm_mode_config_funcs in docs.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1462982962-10530-3-git-send-email-noralf@tronnes.org

Documentation/DocBook/gpu.tmpl

@@ -1615,6 +1615,11 @@ void intel_crt_init(struct drm_device *dev)
 !Pdrivers/gpu/drm/drm_fb_helper.c fbdev helpers
 !Edrivers/gpu/drm/drm_fb_helper.c
 !Iinclude/drm/drm_fb_helper.h
+    </sect2>
+    <sect2>
+      <title>Framebuffer CMA Helper Functions Reference</title>
+!Pdrivers/gpu/drm/drm_fb_cma_helper.c framebuffer cma helper functions
+!Edrivers/gpu/drm/drm_fb_cma_helper.c
     </sect2>
     <sect2>
       <title>Display Port Helper Functions Reference</title>

drivers/gpu/drm/drm_fb_cma_helper.c

@@ -43,14 +43,12 @@ struct drm_fbdev_cma {
  * Provides helper functions for creating a cma (contiguous memory allocator)
  * backed framebuffer.
  *
- * drm_fb_cma_create() is used in the
- * (struct drm_mode_config_funcs *)->fb_create callback function to create the
- * cma backed framebuffer.
+ * drm_fb_cma_create() is used in the &drm_mode_config_funcs ->fb_create
+ * callback function to create a cma backed framebuffer.
  *
  * An fbdev framebuffer backed by cma is also available by calling
  * drm_fbdev_cma_init(). drm_fbdev_cma_fini() tears it down.
- * If CONFIG_FB_DEFERRED_IO is enabled and the callback
- * (struct drm_framebuffer_funcs)->dirty is set, fb_deferred_io
+ * If the &drm_framebuffer_funcs ->dirty callback is set, fb_deferred_io
  * will be set up automatically. dirty() is called by
  * drm_fb_helper_deferred_io() in process context (struct delayed_work).
  *