Merge branch 'LiteETH-driver'

Joel Stanley says:

====================
net: Add LiteETH network driver

This adds a driver for the LiteX network device, LiteEth.

v4 Fixes the bindings and adds r-b tags from Gabriel and Rob.

v3 Updates the bindings to describe the slots in a way that makes more
sense for the hardware, instead of trying to fit some existing
properties. The driver is updated to use these bindings, and fix some
issues pointed out by Gabriel.

v2 Addresses feedback from Jakub, with detailed changes in each patch.

It also moves to the litex register accessors so the system works on big
endian litex platforms. I tested with mor1k on an Arty A7-100T.

I have removed the mdio aspects of the driver as they are not needed for
basic operation. I will continue to work on adding support in the
future, but I don't think it needs to block the mac driver going in.

The binding describes the mdio registers, and has been fixed to not show
any warnings against dtschema master.

LiteEth is a simple driver for the FPGA based Ethernet device used in various
RISC-V, PowerPC's microwatt, OpenRISC's mor1k and other FPGA based
systems on chip.
====================

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