Service core statistics MT safety

[Mattias Rönnblom]

Hi.

Is it safe to enable stats on MT safe services?

https://github.com/DPDK/dpdk/blob/main/lib/eal/common/rte_service.c#L366

It seems to me this would have to be an __atomic_add for this code to 
produce deterministic results.

Best regards,
        Mattias