drm/i915/ddi: s/crtc->config/old_crtc_state in haswell_crtc_disable()

crtc->config points to the old crtc state at the point
display.crtc_disable() is called, so use the more descriptive pointer
instead.

v2:
- Convert one remaining instance of the ptr in the function. (Ville)

Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180613170710.15080-2-imre.deak@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -5814,7 +5814,7 @@ static void haswell_crtc_disable(struct intel_crtc_state *old_crtc_state,
 	struct drm_crtc *crtc = old_crtc_state->base.crtc;
 	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	enum transcoder cpu_transcoder = intel_crtc->config->cpu_transcoder;
+	enum transcoder cpu_transcoder = old_crtc_state->cpu_transcoder;
 
 	intel_encoders_disable(crtc, old_crtc_state, old_state);
 
@@ -5825,8 +5825,8 @@ static void haswell_crtc_disable(struct intel_crtc_state *old_crtc_state,
 	if (!transcoder_is_dsi(cpu_transcoder))
 		intel_disable_pipe(old_crtc_state);
 
-	if (intel_crtc_has_type(intel_crtc->config, INTEL_OUTPUT_DP_MST))
-		intel_ddi_set_vc_payload_alloc(intel_crtc->config, false);
+	if (intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DP_MST))
+		intel_ddi_set_vc_payload_alloc(old_crtc_state, false);
 
 	if (!transcoder_is_dsi(cpu_transcoder))
 		intel_ddi_disable_transcoder_func(dev_priv, cpu_transcoder);
@@ -5837,7 +5837,7 @@ static void haswell_crtc_disable(struct intel_crtc_state *old_crtc_state,
 		ironlake_pfit_disable(intel_crtc, false);
 
 	if (!transcoder_is_dsi(cpu_transcoder))
-		intel_ddi_disable_pipe_clock(intel_crtc->config);
+		intel_ddi_disable_pipe_clock(old_crtc_state);
 
 	intel_encoders_post_disable(crtc, old_crtc_state, old_state);