configuration of memseg lists number

[Thomas Monjalon]

Hello,

While looking at Seastar, I see it uses this patch on top of DPDK:

	build: add meson options of max_memseg_lists

	RTE_MAX_MEMSEG_LISTS = 128 is not enough for high-memory machines,
	in our case, we need to increase it to 8192.
	so add an option so user can override it.

	https://github.com/scylladb/dpdk/commit/cafaa3cf457584de

I think we could allow to configure this at runtime,
as we did already for RTE_MAX_MEMZONE:
we've added rte_memzone_max_set() / rte_memzone_max_get().

Opinions, comments, volunteers?