drm/i915/bdw: on Broadwell, the panel fitter is on the pipe

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>

drivers/gpu/drm/i915/intel_ddi.c

@@ -756,7 +756,8 @@ void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_encoder *intel_encoder = intel_ddi_get_crtc_encoder(crtc);
 	struct drm_encoder *encoder = &intel_encoder->base;
-	struct drm_i915_private *dev_priv = crtc->dev->dev_private;
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	enum pipe pipe = intel_crtc->pipe;
 	enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
 	enum port port = intel_ddi_get_encoder_port(intel_encoder);
@@ -792,10 +793,11 @@ void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
 	if (cpu_transcoder == TRANSCODER_EDP) {
 		switch (pipe) {
 		case PIPE_A:
-			/* Can only use the always-on power well for eDP when
-			 * not using the panel fitter, and when not using motion
-			  * blur mitigation (which we don't support). */
-			if (intel_crtc->config.pch_pfit.enabled)
+			/* On Haswell, can only use the always-on power well for
+			 * eDP when not using the panel fitter, and when not
+			 * using motion blur mitigation (which we don't
+			 * support). */
+			if (IS_HASWELL(dev) && intel_crtc->config.pch_pfit.enabled)
 				temp |= TRANS_DDI_EDP_INPUT_A_ONOFF;
 			else
 				temp |= TRANS_DDI_EDP_INPUT_A_ON;