af-packet: use per CPU hash in bypass

af-packet: use per CPU hash in bypass

eBPF has a data type which is a per CPU array. By adding one element
to the array it is in fact added to all per CPU arrays in the kernel.
This allows to have a lockless structure in the kernel even when doing
counter update.

In userspace, we need to update the flow bypass code to fetch all
elements of the per CPU arrays.