[M] Change in coreboot[master]: soc/intel/ehl: Add EHL MDIO operation

[Mario Scheithauer (Code Review)]

Attention is currently required from: Mario Scheithauer, Angel Pons, Lean Sheng Tan.

Hello build bot (Jenkins), Angel Pons, Lean Sheng Tan, Werner Zeh,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/69383

to look at the new patch set (#4).

Change subject: soc/intel/ehl: Add EHL MDIO operation
......................................................................

soc/intel/ehl: Add EHL MDIO operation

Previously, MDIO read/write access was only necessary for internal GbE
TSN controller. For external MDIO access, it is necessary to provide a
more general solution. This MDIO operation provides a read and write
function which can be also used on mainboard level.

Change-Id: I5d1b9dd2f2ba8c18291fff314c13f0c3851784aa
Signed-off-by: Mario Scheithauer 
---
M src/soc/intel/elkhartlake/Makefile.inc
A src/soc/intel/elkhartlake/include/soc/mdio.h
M src/soc/intel/elkhartlake/include/soc/tsn_gbe.h
A src/soc/intel/elkhartlake/mdio.c
M src/soc/intel/elkhartlake/tsn_gbe.c
5 files changed, 149 insertions(+), 83 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/83/69383/4