libmbim: Update owners

BUG=None
TEST=None

Change-Id: I3031ed48f0db1bcd0c6507efe1e102b04a851602
diff --git a/OWNERS b/OWNERS
index 9df7ded..3f3efb9 100644
--- a/OWNERS
+++ b/OWNERS
@@ -3,3 +3,4 @@
 pholla@chromium.org
 andrewlassalle@chromium.org
 madhavadas@google.com
+nmarupaka@google.com