graphics: update owners

With olv@ no longer on the graphics team we need to update the
owners file to remove him and add new owners.

For composer the new owners are: lpy@ and vhau@
For allocator/mapper the new owner is: marissaw@

Test: N/A
Change-Id: Ied297e9446d480629155e1d9a96575ee518c2135
diff --git a/graphics/composer/2.1/vts/OWNERS b/graphics/composer/2.1/vts/OWNERS
index ef69d7c..0b42d2e 100644
--- a/graphics/composer/2.1/vts/OWNERS
+++ b/graphics/composer/2.1/vts/OWNERS
@@ -1,6 +1,7 @@
 # Graphics team
-olv@google.com
+lpy@google.com
+vhau@google.com
 
 # VTS team
 yim@google.com
-zhuoyao@google.com
\ No newline at end of file
+zhuoyao@google.com