We need to set the 'allow force wake' bit to enable forcewake handling
later on.

v2: split from clock gating patch (Jani)
    check for allowwakeack (Ville)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>