docs(maintainers): add Chris Kay to AMU and MPMM

Change-Id: I8c775c8cac4fbbb2904952747a9572a71aff37b4
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/docs/about/maintainers.rst b/docs/about/maintainers.rst
index 7db81fc..337dde6 100644
--- a/docs/about/maintainers.rst
+++ b/docs/about/maintainers.rst
@@ -217,6 +217,8 @@
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 :|M|: Alexei Fedorov <Alexei.Fedorov@arm.com>
 :|G|: `AlexeiFedorov`_
+:|M|: Chris Kay <chris.kay@arm.com>
+:|G|: `CJKay`_
 :|F|: lib/extensions/amu/
 
 Memory Partitioning And Monitoring (MPAM) extensions
@@ -326,6 +328,13 @@
 :|F|: drivers/scmi-msg
 :|F|: include/drivers/scmi\*
 
+Max Power Mitigation Mechanism (MPMM)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+:|M|: Chris Kay <chris.kay@arm.com>
+:|G|: `CJKay`_
+:|F|: include/lib/mpmm/
+:|F|: lib/mpmm/
+
 Platform Ports
 ~~~~~~~~~~~~~~