staging: lustre: libcfs: discard LASSERT_CHECKED

This macro isn't used, and comment is about some earlier version
of the lustre code that never reached the mainline kernel.
Just discard it.

Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>