So you can use the panel fitter while the power well is disabled and
you also don't need to set the "pipe" bit.

v2: Rebased on top of Jesse's pfit refactor, which moved pfit state
into the pipe_config.

v3: Rebase on top of the latest Haswell/panel fitter rework, which
neatly resolves a FIXME we have in this patch here:

v4: Rebase on top of the new power domain framework.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v1)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>