docs: perf: move to the admin-guide

The perf infrastructure is used for userspace to track issues.
At least a good part of what's described here is related to
it.

So, add it to the admin-guide.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index db96cd4..b8ce346 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1155,7 +1155,7 @@
 M:	Khuong Dinh <khuong@os.amperecomputing.com>
 S:	Supported
 F:	drivers/perf/xgene_pmu.c
-F:	Documentation/perf/xgene-pmu.rst
+F:	Documentation/admin-guide/perf/xgene-pmu.rst
 F:	Documentation/devicetree/bindings/perf/apm-xgene-pmu.txt
 
 APTINA CAMERA SENSOR PLL
@@ -7262,7 +7262,7 @@
 W:	http://www.hisilicon.com
 S:	Supported
 F:	drivers/perf/hisilicon
-F:	Documentation/perf/hisi-pmu.rst
+F:	Documentation/admin-guide/perf/hisi-pmu.rst
 
 HISILICON ROCE DRIVER
 M:	Lijun Ou <oulijun@huawei.com>