While we only need to restore pipe B/C interrupt registers on BDW when
enabling the power well, skylake a bit more flexible and we'll also need
to restore the pipe A registers as it has its own power well that can be
toggled.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>