[XL] Change in coreboot[main]: mb/lenovo: Add ThinkCentre M920q (Cannon Lake)

[Felix Singer (Code Review)]

Attention is currently required from: Alexander Couzens, Maciej Pijanowski, Michał Kopeć, Paul Menzel.

Felix Singer has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80609?usp=email )

Change subject: mb/lenovo: Add ThinkCentre M920q (Cannon Lake)
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Patch Set 4:

(2 comments)

File src/mainboard/lenovo/m920q/acpi/ec.asl:

PS4: 
```
/* SPDX-License-Identifier: CC-PDDC */

/* Please update the license if adding licensable material. */
```

File src/mainboard/lenovo/m920q/acpi/mainboard.asl:

PS4: 
```
/* SPDX-License-Identifier: CC-PDDC */

/* Please update the license if adding licensable material. */
```