Enable the keymaster logger in the default Keymint

This solution was adopted from Cuttlefish's host side Keymint
implementation: I22bde00aed311c6774f83acc08a2c21e6e75141f.

Bug: 296983430
Test: Tested with Cuttlefish that the logs are present in logcat.
Change-Id: I942b0200bb164a2a865b255c6f26d628cbd345a4
diff --git a/security/keymint/aidl/default/service.cpp b/security/keymint/aidl/default/service.cpp
index dc0c618..10cbf07 100644
--- a/security/keymint/aidl/default/service.cpp
+++ b/security/keymint/aidl/default/service.cpp
@@ -44,6 +44,8 @@
 }
 
 int main() {
+    // The global logger object required by keymaster's logging macros in keymaster/logger.h.
+    keymaster::SoftKeymasterLogger km_logger;
     // Zero threads seems like a useless pool, but below we'll join this thread to it, increasing
     // the pool size to 1.
     ABinderProcess_setThreadPoolMaxThreadCount(0);