gd_draw_event shouldn't try to repaint if surface does not exist
for the VC.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
Message-Id: <20211104065153.28897-4-dongwon.kim@intel.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>