LU-12477 llite: remove unused ll_teardown_mmaps()

LU-12477 llite: remove unused ll_teardown_mmaps()

The ll_teardown_mmaps() function is no longer used and can be
removed.

Fixes: f114d4dac6f8 ("LU-12477 llite: use generic_error_remove_page()")
Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I42506210e028da3bf8036a28d4d61b1e7d3ebbe5
Reviewed-on: https://review.whamcloud.com/41086
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Oleg Drokin <green@whamcloud.com>