Revert "Disallow shrinking threadpool size once started."

This reverts commit e52a3b607d8b6be8c550a0e0de0e48f630514e5d.

Reason for revert: caught bug in b/150901303, but will temporarily revert until it can be fixed.

Change-Id: Ia8e37395e0d000d247c0ffa4ac9243aab699d09b
diff --git a/libs/binder/ProcessState.cpp b/libs/binder/ProcessState.cpp
index 6627618..c0f5e31 100644
--- a/libs/binder/ProcessState.cpp
+++ b/libs/binder/ProcessState.cpp
@@ -324,8 +324,6 @@
 }
 
 status_t ProcessState::setThreadPoolMaxThreadCount(size_t maxThreads) {
-    LOG_ALWAYS_FATAL_IF(mThreadPoolStarted && maxThreads < mMaxThreads,
-           "Binder threadpool cannot be shrunk after starting");
     status_t result = NO_ERROR;
     if (ioctl(mDriverFD, BINDER_SET_MAX_THREADS, &maxThreads) != -1) {
         mMaxThreads = maxThreads;