[tools/perf] Update OWNERS to state that petrcermak@ can review memory-infra related changes

Review-Url: https://codereview.chromium.org/2300233003
Cr-Commit-Position: refs/heads/master@{#416253}

tools/perf/OWNERS

@@ -10,7 +10,7 @@ zhenw@chromium.org
 # Simple rubberstamp-only oilpan-related changes.
 peria@chromium.org
 
-# For system health related changes.
+# For system health & memory-infra related changes.
 petrcermak@chromium.org
 
 # emeritus: