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/allocator/2.0/default/OWNERS b/graphics/allocator/2.0/default/OWNERS
index 3aa5fa1..273cb4c 100644
--- a/graphics/allocator/2.0/default/OWNERS
+++ b/graphics/allocator/2.0/default/OWNERS
@@ -1,4 +1,4 @@
 # Graphics team
 jessehall@google.com
-olv@google.com
+marissaw@google.com
 stoza@google.com
diff --git a/graphics/allocator/2.0/utils/OWNERS b/graphics/allocator/2.0/utils/OWNERS
index 3aa5fa1..273cb4c 100644
--- a/graphics/allocator/2.0/utils/OWNERS
+++ b/graphics/allocator/2.0/utils/OWNERS
@@ -1,4 +1,4 @@
 # Graphics team
 jessehall@google.com
-olv@google.com
+marissaw@google.com
 stoza@google.com