docs/vm: move numa_memory_policy.rst to Documentation/admin-guide/mm

The document describes userspace API and as such it belongs to
Documentation/admin-guide/mm

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst
index ad28644..a69aa69 100644
--- a/Documentation/admin-guide/mm/index.rst
+++ b/Documentation/admin-guide/mm/index.rst
@@ -24,6 +24,7 @@
    hugetlbpage
    idle_page_tracking
    ksm
+   numa_memory_policy
    pagemap
    soft-dirty
    userfaultfd