Remove Foreground Boost CPUSet

This functionality was removed at
https://android.googlesource.com/platform/frameworks/base/+/a712d4058f6f85268838
diff --git a/init.dragon.rc b/init.dragon.rc
index 2f5f389..77309cc 100644
--- a/init.dragon.rc
+++ b/init.dragon.rc
@@ -135,7 +135,6 @@
     # update foreground cpuset now that processors are up
     # reserve CPU 3 for the top app
     write /dev/cpuset/foreground/cpus 0-2
-    write /dev/cpuset/foreground/boost/cpus 0-2
     write /dev/cpuset/background/cpus 0
     write /dev/cpuset/system-background/cpus 0-1
     write /dev/cpuset/top-app/cpus 0-3