owners: Add Andrew and Joel to gpio-naming.md

To help with reviewing the eventual device tree patches that will flow
from additions to this file, add us as reviewers.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I99c378a54964611a22ab25d0badd29e30d2258cd
diff --git a/OWNERS b/OWNERS
index ebe1b9a..055faa5 100644
--- a/OWNERS
+++ b/OWNERS
@@ -36,11 +36,15 @@
 - patrick@stwcx.xyz
 
 reviewers:
-- anoo@us.ibm.com
 - andrew@aj.id.au
+- anoo@us.ibm.com
 - gmills@linux.vnet.ibm.com
 
 matches:
+- exact: designs/device-tree-gpio-naming.md
+  reviewers:
+  - andrew@aj.id.au
+  - joel@jms.id.au
 - partial_regex: mctp
   reviewers:
   - jk@ozlabs.org
@@ -61,6 +65,9 @@
 - name: Jeremy Kerr
   email: jk@ozlabs.org
   discord: jk
+- name: Joel Stanley
+  email: joel@jms.id.au
+  discord: joel
 - name: Patrick Williams
   email: patrick@stwcx.xyz
   discord: stwcx