docs: fix locations of several documents that got moved

The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/cgroup-v1/00-INDEX b/Documentation/cgroup-v1/00-INDEX
index 106885a..13e0c85 100644
--- a/Documentation/cgroup-v1/00-INDEX
+++ b/Documentation/cgroup-v1/00-INDEX
@@ -8,7 +8,7 @@
 	- CPU Accounting Controller; account CPU usage for groups of tasks.
 cpusets.txt
 	- documents the cpusets feature; assign CPUs and Mem to a set of tasks.
-devices.txt
+admin-guide/devices.rst
 	- Device Whitelist Controller; description, interface and security.
 freezer-subsystem.txt
 	- checkpointing; rationale to not use signals, interface.