drm: add drm_format_helper.c to kerneldoc

Also drop the dstclip parameter sphinx has warned about (leftover from
an earlier patch version).
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190416090533.28374-1-kraxel@redhat.com

Documentation/gpu/drm-kms-helpers.rst

@@ -107,6 +107,12 @@ fbdev Helper Functions Reference
 .. kernel-doc:: drivers/gpu/drm/drm_fb_helper.c
    :export:
 
+format Helper Functions Reference
+=================================
+
+.. kernel-doc:: drivers/gpu/drm/drm_format_helper.c
+   :export:
+
 Framebuffer CMA Helper Functions Reference
 ==========================================
 

drivers/gpu/drm/drm_format_helper.c

@@ -235,7 +235,6 @@ static void drm_fb_xrgb8888_to_rgb888_line(u8 *dbuf, u32 *sbuf,
  * @vaddr: XRGB8888 source buffer
  * @fb: DRM framebuffer
  * @clip: Clip rectangle area to copy
- * @dstclip: Clip destination too.
  *
  * Drivers can use this function for RGB888 devices that don't natively
  * support XRGB8888.