drm/doc: Helpers are not a Midlayer!

I'm devoting all my wrath to that fight, so don't misname it ;-)

v2: Make it clear that this section talks about kms helpers.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Documentation/DocBook/drm.tmpl

@@ -1611,10 +1611,10 @@ void intel_crt_init(struct drm_device *dev)
     </sect2>
   </sect1>
 
-  <!-- Internals: mid-layer helper functions -->
+  <!-- Internals: kms helper functions -->
 
   <sect1>
-    <title>Mid-layer Helper Functions</title>
+    <title>Mode Setting Helper Functions</title>
     <para>
       The CRTC, encoder and connector functions provided by the drivers
       implement the DRM API. They're called by the DRM core and ioctl handlers