Merge branch 'net-collect-tstats-automatically'

Breno Leitao says:

====================
net: collect tstats automatically

The commit 34d21de9

 ("net: Move {l,t,d}stats allocation to core and
convert veth & vrf") added a field in struct_netdevice, which tells what
type of statistics the driver supports.

That field is used primarily to allocate stats structures automatically,
but, it also could leveraged to simplify the drivers even further, such
as, if the driver relies in the default stats collection, then it
doesn't need to assign to .ndo_get_stats64. That means that drivers only
assign functions to .ndo_get_stats64 if they are using something
special.

I started to move some of these drivers[1][2][3] to use the core
allocation, and with this change in, I just need to touch the driver
once, and be able to simplify the whole stats allocation and collection
for generic case.

There are 44 devices today that could benefit from this simplification.

	# grep -r .ndo_get_stats64 | grep dev_get_tstats64 | wc -l
	44

As of today, netnext only has the `sit` driver fully ported to core
stats allocation, hence the second patch.

Links:
[1] https://lore.kernel.org/all/20240227182338.2739884-1-leitao@debian.org/
[2] https://lore.kernel.org/all/20240222144117.1370101-1-leitao@debian.org/
[3] https://lore.kernel.org/all/20240223115839.3572852-1-leitao@debian.org/
====================

Link: https://lore.kernel.org/r/20240228113125.3473685-1-leitao@debian.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>