drm/i915: Use pipe_config's cpu_transcoder for reading encoder hw state

The get_config() functions for ddi and dp_mst, used to read the value
of cpu_transcoder from the crtc->config instead of the state passed as
an argument. On the hardware state readout path, that happens to work
since the proper value is written to it before encoder->get_config() is
called. However, in the check_crtc() path, the state will be read from
the cpu_transcoder in the software tracking, instead of the one just
read out from hw. Using the field in the supplied intel_crtc_state
should do the right thing in both cases.

v2: Fix intel_ddi_get_config() too. (Ander)

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index ad8b73d..f14e8a2 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2038,7 +2038,7 @@
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
-	enum transcoder cpu_transcoder = intel_crtc->config->cpu_transcoder;
+	enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
 	struct intel_hdmi *intel_hdmi;
 	u32 temp, flags = 0;