drm/i915: Prepare the mode readout for hw vs. uapi state split

Prepare the mode readout for the uapi vs. hw state split.
We'll want to do all readout into the hw state.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190927131432.15978-4-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -16803,7 +16803,7 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
 			crtc->base.mode.hdisplay = crtc_state->pipe_src_w;
 			crtc->base.mode.vdisplay = crtc_state->pipe_src_h;
 			intel_mode_from_pipe_config(&crtc_state->base.adjusted_mode, crtc_state);
-			WARN_ON(drm_atomic_set_mode_for_crtc(crtc->base.state, &crtc->base.mode));
+			WARN_ON(drm_atomic_set_mode_for_crtc(&crtc_state->base, &crtc->base.mode));
 
 			/*
 			 * The initial mode needs to be set in order to keep