drm: Ignore drm_gem_vram_mm_funcs in generated documentation

The documentation tools interpret drm_gem_vram_mm_funcs as function and
there appears to be no way of inline-documenting constants. This results
in a warning by 'make htmldocs'. For now, removing drm_gem_vram_mm_funcs
from generated documentation works around the issue.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20190604111330.25324-1-tzimmermann@suse.de
Fixes: 5c9dcacf ("drm: Add default instance for VRAM MM callback functions")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/drm_gem_vram_helper.c

@@ -585,7 +585,7 @@ int drm_gem_vram_bo_driver_verify_access(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(drm_gem_vram_bo_driver_verify_access);
 
-/**
+/*
  * drm_gem_vram_mm_funcs - Functions for &struct drm_vram_mm
  *
  * Most users of @struct drm_gem_vram_object will also use