Removed build time variable ENABLE_CPUSETS.

Use runtime check, cpuset_enabled(), instead of build time varianble
usually set in BoardConfog.mk.

Bug: 34726944

Test: Tested on Sailfish
      without cpuset mounted
      with cpuset mounted, but without schedtune
      with cpuset mounted and with schedtune

Change-Id: I00153628db62abfbaa0ba75d571ba1bda0611ff3
diff --git a/services/surfaceflinger/main_surfaceflinger.cpp b/services/surfaceflinger/main_surfaceflinger.cpp
index 53a63bd..f151087 100644
--- a/services/surfaceflinger/main_surfaceflinger.cpp
+++ b/services/surfaceflinger/main_surfaceflinger.cpp
@@ -45,12 +45,10 @@
 
     set_sched_policy(0, SP_FOREGROUND);
 
-#ifdef ENABLE_CPUSETS
     // Put most SurfaceFlinger threads in the system-background cpuset
     // Keeps us from unnecessarily using big cores
     // Do this after the binder thread pool init
-    set_cpuset_policy(0, SP_SYSTEM);
-#endif
+    if (cpusets_enabled()) set_cpuset_policy(0, SP_SYSTEM);
 
     // initialize before clients can connect
     flinger->init();