drm/i915: avoid hanging on to a stale pointer to raw_edid.

drm_get_edid will store edid into raw_edid, so when freeing edid memory,
at the same time clean raw_edid pointer.
Signed-off-by: NMa Ling <ling.ma@intel.com>
[anholt: Note that raw_edid is not currently used anywhere]
Signed-off-by: NEric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_modes.c

@@ -76,6 +76,7 @@ int intel_ddc_get_modes(struct intel_output *intel_output)
 		drm_mode_connector_update_edid_property(&intel_output->base,
 							edid);
 		ret = drm_add_edid_modes(&intel_output->base, edid);
+		intel_output->base.display_info.raw_edid = NULL;
 		kfree(edid);
 	}