[coreboot] [RFH] Testers with Intel devices for common SMM/SMI handler

[Paul Menzel]

Dear coreboot folks,

Arthur did great work and unified and improved a lot of code under the
topic *common_smm_smihandler* [1].

To avoid regressions, could everyone with the appropriate hardware
please test [2], and comment on the change-set with the test result?

The instructions below should build fetch the required changes, and
build a new image.

```
$ git fetch https://review.coreboot.org/coreboot refs/changes/06/25606/6 && git checkout -b common_smm_smihandler FETCH_HEAD
$ make olddefconfig
$ make clean
$ make
```

Kind regards

Paul

[1] https://review.coreboot.org/#/q/status:open+project:coreboot+branch:master+t...
[2] https://review.coreboot.org/#/c/coreboot/+/25606/