Merge branch 'New-DSA-driver-for-VSC9953-Seville-switch'

Merge branch 'New-DSA-driver-for-VSC9953-Seville-switch'

Vladimir Oltean says:

====================
New DSA driver for VSC9953 Seville switch

Looking at the Felix and Ocelot drivers, Maxim asked if it would be
possible to use them as a base for a new driver for the Seville switch
inside NXP T1040. Turns out, it is! The result is that the mscc_felix
driver was extended to probe on Seville.

The biggest challenge seems to be getting register read/write API
generic enough to cover such wild bitfield variations between hardware
generations.

Currently, both felix and seville are built under the same kernel config
option (NET_DSA_MSCC_FELIX). This has both some advantages (no need to
duplicate the Lynx PCS code from felix_vsc9959.c) and some disadvantages
(Seville needs to depend on PCI and on ENETC_MDIO). This will be further
refined as time progresses.

The driver has been completely reviewed. Previous submission was here,
it wasn't accepted due to a conflict with Mark Brown's tree, very late
in the release cycle:

https://patchwork.ozlabs.org/project/netdev/cover/20200531122640.1375715-1-olteanv@gmail.com/

So this is more of a repost, with the only changes being related to
rebasing on top of the cleanup I had to do in Ocelot.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>