audioserver: Increase hwbinder thread pool size

Use 4 threads instead of default 1, since audioserver
serves many clients.

Bug: 67203473
Test: audio still works
Change-Id: I7b191974f1a912fd8adf0096c3a1abf33a3d12fa

media/audioserver/Android.mk

@@ -13,6 +13,8 @@ LOCAL_SHARED_LIBRARIES := \
 	libbinder \
 	libcutils \
 	liblog \
+	libhidltransport \
+	libhwbinder \
 	libmedialogservice \
 	libnbaio \
 	libsoundtriggerservice \

media/audioserver/main_audioserver.cpp

@@ -25,6 +25,7 @@
 #include <binder/IPCThreadState.h>
 #include <binder/ProcessState.h>
 #include <binder/IServiceManager.h>
+#include <hidl/HidlTransportSupport.h>
 #include <utils/Log.h>
 
 // from LOCAL_C_INCLUDES
@@ -124,6 +125,7 @@ int main(int argc __unused, char **argv)
             prctl(PR_SET_PDEATHSIG, SIGKILL);   // if parent media.log dies before me, kill me also
             setpgid(0, 0);                      // but if I die first, don't kill my parent
         }
+        android::hardware::configureRpcThreadpool(4, false /*callerWillJoin*/);
         sp<ProcessState> proc(ProcessState::self());
         sp<IServiceManager> sm = defaultServiceManager();
         ALOGI("ServiceManager: %p", sm.get());