Add zygote to the foreground cpuset.

This ensures that newly forked zygote processes will end up
in the corret cpuset.

bug 23751126

Change-Id: I987a2828cf2504963f1317d17f0b51d26cf22a70
diff --git a/rootdir/init.zygote64.rc b/rootdir/init.zygote64.rc
index afb6d63..5497524 100644
--- a/rootdir/init.zygote64.rc
+++ b/rootdir/init.zygote64.rc
@@ -5,4 +5,4 @@
     onrestart write /sys/power/state on
     onrestart restart media
     onrestart restart netd
-
+    writepid /dev/cpuset/foreground/tasks