drm/i915: Use the new __drm_atomic_helper_crtc_reset() helper.

i915 has its own hw readout and doesn't use the reset helpers directly.
Still it has 2 places where it initialises the crtc_state. Fix those
by calling __drm_atomic_helper_crtc_reset().
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Not-nacked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190301125627.7285-8-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -14526,9 +14526,8 @@ static int intel_crtc_init(struct drm_i915_private *dev_priv, enum pipe pipe)
 		ret = -ENOMEM;
 		goto fail;
 	}
+	__drm_atomic_helper_crtc_reset(&intel_crtc->base, &crtc_state->base);
 	intel_crtc->config = crtc_state;
-	intel_crtc->base.state = &crtc_state->base;
-	crtc_state->base.crtc = &intel_crtc->base;
 
 	primary = intel_primary_plane_create(dev_priv, pipe);
 	if (IS_ERR(primary)) {
@@ -16070,7 +16069,7 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
 
 		__drm_atomic_helper_crtc_destroy_state(&crtc_state->base);
 		memset(crtc_state, 0, sizeof(*crtc_state));
-		crtc_state->base.crtc = &crtc->base;
+		__drm_atomic_helper_crtc_reset(&crtc->base, &crtc_state->base);
 
 		crtc_state->base.active = crtc_state->base.enable =
 			dev_priv->display.get_pipe_config(crtc, crtc_state);