Fix default keymaster so it doesn't start an extra thread.

Bug: 80102279
Bug: 80251973
Test: N/A; this keymaster exists only for policy compliance. It's never used.
Change-Id: I45f0eefd9abdd02f6774aa52f238040510c5d62c
diff --git a/keymaster/4.0/default/service.cpp b/keymaster/4.0/default/service.cpp
index cfb960a..fdcc6ba 100644
--- a/keymaster/4.0/default/service.cpp
+++ b/keymaster/4.0/default/service.cpp
@@ -24,6 +24,7 @@
 using android::hardware::keymaster::V4_0::SecurityLevel;
 
 int main() {
+    ::android::hardware::configureRpcThreadpool(1, true /* willJoinThreadpool */);
     auto keymaster = ::keymaster::V4_0::ng::CreateKeymasterDevice(SecurityLevel::SOFTWARE);
     auto status = keymaster->registerAsService();
     if (status != android::OK) {