Add OWNERS in frameworks/av

* Owners are selected from top CL approvals or owners.
  They will be suggested to review/approve future CLs.
* OWNERS files are recognized by the new find-owners plugin, see .md files in
  https://gerrit.googlesource.com/plugins/find-owners/+/master/src/main/resources/Documentation/

Test: build/make/tools/checkowners.py -c -v OWNERS
Change-Id: I7c848855a2d7a0d7f33123ea4ef5c2d03977b495
diff --git a/media/OWNERS b/media/OWNERS
new file mode 100644
index 0000000..cd4afb4
--- /dev/null
+++ b/media/OWNERS
@@ -0,0 +1,5 @@
+hunga@google.com
+lajos@google.com
+marcone@google.com
+robertshih@google.com
+wjia@google.com