Add Elkhart Lake support

Elkhart Lake has a chipset called Mule Creek Canyon which is quite
compatible with 300 series chipsets. There are a few differences though,
e.g. different encoding for the SPI clock values for read and write in
the FLCOMP register. In addition Elkhart Lake has a new PCI device ID
for the SPI controller which is added, too.

TEST=Read and flash complete flash on Siemens MC EHL1

Change-Id: I711e39a3ec9cd7098389231eaa1cb864d615a475
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
---
M chipset_enable.c
M ich_descriptors.c
M ichspi.c
M programmer.h
M util/ich_descriptors_tool/ich_descriptors_tool.c
5 files changed, 51 insertions(+), 8 deletions(-)