Merge branch 'move-siena-into-a-separate-subdirectory'

Martin Habets says:

====================
Move Siena into a separate subdirectory

The Siena NICs (SFN5000 and SFN6000 series) went EOL in November 2021.
Most of these adapters have been remove from our test labs, and testing
has been reduced to a minimum.

This patch series creates a separate kernel module for the Siena architecture,
analogous to what was done for Falcon some years ago.
This reduces our maintenance for the sfc.ko module, and allows us to
enhance the EF10 and EF100 drivers without the risk of breaking Siena NICs.

After this series further enhancements are needed to differentiate the
new kernel module from sfc.ko, and the Siena code can be removed from sfc.ko.
Thes will be posted as a small follow-up series.
The Siena module is not built by default, but can be enabled
using Kconfig option SFC_SIENA. This will create module sfc-siena.ko.

	Patches

Patches 1-3 establish the code base for the Siena driver.
Patches 4-10 ensure the allyesconfig build succeeds.
Patch 11 adds the basic Siena module.

I do not expect patch 1 through 3 to be reviewed, they are FYI only.
No checkpatch issues were resolved as part of these, but they
were fixed in the subsequent patches.

	Testing

Various build tests were done such as allyesconfig, W=1 and sparse.
The new sfc-siena.ko and sfc.ko modules were tested on a machine with both
these NICs in them, and several tests were run on both drivers.
====================

Link: https://lore.kernel.org/r/165211018297.5289.9658523545298485394.stgit@palantir17.mph.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>