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>

Documentation/filesystems/proc.txt

@@ -566,7 +566,7 @@ address   policy    mapping details
 
 Where:
 "address" is the starting address for the mapping;
-"policy" reports the NUMA memory policy set for the mapping (see vm/numa_memory_policy.txt);
+"policy" reports the NUMA memory policy set for the mapping (see Documentation/admin-guide/mm/numa_memory_policy.rst);
 "mapping details" summarizes mapping data such as mapping type, page usage counters,
 node locality page counters (N0 == node0, N1 == node1, ...) and the kernel page
 size, in KB, that is backing the mapping up.