wpa_cli log level

参考：

log_level <level> [<timestamp>] = update the log level/timestamp
log_level = display the current log level and log options

+static const char * debug_level_str(int level)
+{
+	switch (level) {
+	case MSG_EXCESSIVE:
+		return "EXCESSIVE";
+	case MSG_MSGDUMP:
+		return "MSGDUMP";
+	case MSG_DEBUG:
+		return "DEBUG";
+	case MSG_INFO:
+		return "INFO";
+	case MSG_WARNING:
+		return "WARNING";
+	case MSG_ERROR:
+		return "ERROR";
+	default:
+		return "?";
+	}
+}

默认的 excessive 即打印所有级别。