drm/i915: Eliminate some encoder->crtc usage from SDVO code

Extract the current crtc from the crtc state rather than via
the legacy encoder->crtc pointer whenever possible.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171031205123.13123-4-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1512,7 +1512,7 @@ static void intel_disable_sdvo(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_sdvo *intel_sdvo = to_sdvo(encoder);
-	struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
+	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->base.crtc);
 	u32 temp;
 
 	intel_sdvo_set_active_outputs(intel_sdvo, 0);
@@ -1571,7 +1571,7 @@ static void intel_enable_sdvo(struct intel_encoder *encoder,
 	struct drm_device *dev = encoder->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_sdvo *intel_sdvo = to_sdvo(encoder);
-	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
+	struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->base.crtc);
 	u32 temp;
 	bool input1, input2;
 	int i;