drm/gem: Export drm_gem_lru_move_tail_locked()

Export the locked version or lru's move_tail().

Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/527835/
Link: https://lore.kernel.org/r/20230320144356.803762-7-robdclark@gmail.com