v2: Use the new function, gen6_init_rps_frequencies() (Damien)

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> (v1)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>