After we removed all the intermediate abstractions, we can rename
these functions to just hsw_{en,dis}able_pc8.

v2: - Rebase.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>