Documenation: update cgroup's document path

cgroup's document path is changed to "cgroup-v1". update it.

Signed-off-by: seokhoon.yoon <iamyooon@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/vm/page_migration b/Documentation/vm/page_migration
index fea5c08..344d2d3 100644
--- a/Documentation/vm/page_migration
+++ b/Documentation/vm/page_migration
@@ -38,7 +38,7 @@
 Larger installations usually partition the system using cpusets into
 sections of nodes. Paul Jackson has equipped cpusets with the ability to
 move pages when a task is moved to another cpuset (See
-Documentation/cgroups/cpusets.txt).
+Documentation/cgroup-v1/cpusets.txt).
 Cpusets allows the automation of process locality. If a task is moved to
 a new cpuset then also all its pages are moved with it so that the
 performance of the process does not sink dramatically. Also the pages