This adds the basic identifiers. Due to the various chip quirks it's not
enough to make MRST support very useful for earlier steppings but that can
follow.

(I'm currently trying to verify which steps actually matter outside Intel
 so I can avoid unneeded stuff going upstream)

[Extracted from original development]
Signed-off-by: NJiebingLi <jiebing.li@intel.com>
[Folds in fixes]
Signed-off-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NChris Ball <cjb@laptop.org>