drivers use of service cores

[Thomas Monjalon]

Hello,

I think we can improve the developer experience for using service cores
from a driver, like finding or allocating a service core.
We may take some code and ideas from sfc and nfp drivers,
like in these functions:
	nfp_map_service()
	sfc_mae_counter_service_register()
	sfc_get_service_lcore()

If it is not possible to use a service core,
we could default to using a control thread.
So the driver would never fail because of a thread initialization.

What do you think about proposing such a high level API
in order to get more drivers using it?