staging/lustre/lov: make lov_lsm_alloc() static

It's not used anywhere outside of this file.
Highlighted by sparse.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>