QNX: Use slog2info on pure QNX devices for debug output

If available, slog2info should be used even for pure QNX devices
to get hold of the debug output.

Task-number: QTCREATORBUG-10442

Change-Id: If85855e94803a4b8648e84c0295bfdd2271e8d76
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>