Netd unsolicited event porting

Use another buffer to log unsolicited event.

Test: built, flashed, booted
Test: 1. manual test datacall/wifi work
      2. manual test tethering work
      3. run cts StrictModeTest pass
      4. manual test data alert work
      5. manual idletimer work

Change-Id: I1e4ed360b0c9d60c14bc7f0ffdf578fc557d3643
diff --git a/server/Controllers.h b/server/Controllers.h
index edd6770..52c2809 100644
--- a/server/Controllers.h
+++ b/server/Controllers.h
@@ -74,6 +74,7 @@
 };
 
 extern netdutils::Log gLog;
+extern netdutils::Log gUnsolicitedLog;
 extern Controllers* gCtls;
 
 }  // namespace net