drm/i915: Remove get_existing_crtc_state

get_existing_crtc_state is currently unused, get rid of it.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180409124656.39886-2-maarten.lankhorst@linux.intel.comReviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/i915/intel_drv.h

@@ -2095,20 +2095,6 @@ intel_atomic_get_crtc_state(struct drm_atomic_state *state,
 	return to_intel_crtc_state(crtc_state);
 }
 
-static inline struct intel_crtc_state *
-intel_atomic_get_existing_crtc_state(struct drm_atomic_state *state,
-				     struct intel_crtc *crtc)
-{
-	struct drm_crtc_state *crtc_state;
-
-	crtc_state = drm_atomic_get_existing_crtc_state(state, &crtc->base);
-
-	if (crtc_state)
-		return to_intel_crtc_state(crtc_state);
-	else
-		return NULL;
-}
-
 int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
 			       struct intel_crtc *intel_crtc,
 			       struct intel_crtc_state *crtc_state);