limit number of extra binder threads in SF to 4

it should be enough and it makes debugging easier.

Bug: 6609290
Change-Id: I2341e20cfcfde184fe1ed9b925215f8fa3481ced

cmds/surfaceflinger/main_surfaceflinger.cpp

@@ -20,9 +20,9 @@
 using namespace android;
 
 int main(int argc, char** argv) {
-    SurfaceFlinger::publishAndJoinThreadPool(true);
     // When SF is launched in its own process, limit the number of
     // binder threads to 4.
     ProcessState::self()->setThreadPoolMaxThreadCount(4);
+    SurfaceFlinger::publishAndJoinThreadPool(true);
     return 0;
 }