log, sync: add LOCK logging category, apply it to lock contention

src/sync.cpp

@@ -29,8 +29,8 @@ static_assert(false, "thread_local is not supported");
 #endif
 void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
 {
-    LogPrintf("LOCKCONTENTION: %s\n", pszName);
-    LogPrintf("Locker: %s:%d\n", pszFile, nLine);
+    LogPrint(BCLog::LOCK, "LOCKCONTENTION: %s\n", pszName);
+    LogPrint(BCLog::LOCK, "Locker: %s:%d\n", pszFile, nLine);
 }
 #endif /* DEBUG_LOCKCONTENTION */