drm/i915: duplicate desired mode for use by fbcon.

duplicate the mode into fbcon storage, so when we free modes later
we don't just lose this.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b32a51f..028f5b6 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2310,6 +2310,8 @@
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
+	if (intel_crtc->mode_set.mode)
+		drm_mode_destroy(crtc->dev, intel_crtc->mode_set.mode);
 	drm_crtc_cleanup(crtc);
 	kfree(intel_crtc);
 }