Documentation: update cgroupfs mount point

According to commit 676db4af0430 ("cgroupfs: create /sys/fs/cgroup to
mount cgroupfs on") the canonical mountpoint for the cgroup filesystem
is /sys/fs/cgroup.  Hence, this should be used in the documentation.

Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/vm/hwpoison.txt b/Documentation/vm/hwpoison.txt
index 12f9ba2..5500684 100644
--- a/Documentation/vm/hwpoison.txt
+++ b/Documentation/vm/hwpoison.txt
@@ -129,12 +129,12 @@
 of the memcg.
 
 Example:
-        mkdir /cgroup/hwpoison
+        mkdir /sys/fs/cgroup/mem/hwpoison
 
         usemem -m 100 -s 1000 &
-        echo `jobs -p` > /cgroup/hwpoison/tasks
+        echo `jobs -p` > /sys/fs/cgroup/mem/hwpoison/tasks
 
-        memcg_ino=$(ls -id /cgroup/hwpoison | cut -f1 -d' ')
+        memcg_ino=$(ls -id /sys/fs/cgroup/mem/hwpoison | cut -f1 -d' ')
         echo $memcg_ino > /debug/hwpoison/corrupt-filter-memcg
 
         page-types -p `pidof init`   --hwpoison  # shall do nothing