Merge branch 'net-core-unify-dstats-with-tstats-and-lstats-implement-generic-dstats-collection'

Jeremy Kerr says:

====================
net: core: Unify dstats with tstats and lstats, implement generic dstats collection

The struct pcpu_dstats ("dstats") has a few variations from the other
two stats types (struct pcpu_sw_netstats and struct pcpu_lstats), and
doesn't have generic helpers for collecting the per-cpu stats into a
struct rtnl_link_stats64.

This change unifies dstats with the other types, adds a collection
implementation to the core, and updates the single driver (vrf) to use
this generic implementation.

Of course, questions/comments/etc are most welcome!

v3: https://lore.kernel.org/r/20240605-dstats-v2-0-7fae03f813f3@codeconstruct.com.au
v2: v1: https://lore.kernel.org/r/20240605-dstats-v1-0-1024396e1670@codeconstruct.com.au
====================

Link: https://lore.kernel.org/r/20240607-dstats-v3-0-cc781fe116f7@codeconstruct.com.au


Signed-off-by: Jakub Kicinski <kuba@kernel.org>