drm: Extract drm_bridge.h

We don't want to burry the bridge structures kerneldoc in drm_crtc.h.

Cc: Archit Taneja <archit.taneja@gmail.com>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160831160913.12991-3-daniel.vetter@ffwll.ch
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index 59fa3c1..48fc5a9 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -126,6 +126,13 @@
 .. kernel-doc:: drivers/gpu/drm/drm_bridge.c
    :doc: bridge callbacks
 
+
+Bridge Helper Reference
+-------------------------
+
+.. kernel-doc:: include/drm/drm_bridge.h
+   :internal:
+
 .. kernel-doc:: drivers/gpu/drm/drm_bridge.c
    :export: