slub: fix typo in Documentation/vm/slub.txt
slub_debug=,dentry is correct, not dentry_cache.
Signed-off-by: Itaru Kitayama <i-kitayama@ap.jp.nec.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
authored by Itaru Kitayama and committed by Christoph Lameter 989a7241 6d2144d3