ANDROID: GKI: virtual_device: rename symbol for drm helper

In commit f9403655 ("drm/virtio: New fence for every plane update"),
the virtio-gpu driver was changed from using the
drm_atomic_helper_plane_duplicate_state function to it's own local
version that then calls out to
__drm_atomic_helper_plane_duplicate_state.  Fix up the symbol list to
reflect this change.

Fixes: f9403655 ("drm/virtio: New fence for every plane update")
Change-Id: Ie45c57599c9885dab0b47baeb74a961c0bc4c40a
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>