drm/i915/sdvo: revert bogus kernel-doc comments to normal comments

The comments were never proper kernel-doc, but with SDVO it's not worth
the trouble to make them kernel-doc. Just turn them into normal
comments.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453101588-18008-1-git-send-email-jani.nikula@intel.com