[L] Change in coreboot[main]: mainboard: add Dell Latitude E7240

[Felix Singer (Code Review)]

Attention is currently required from: Arthur Heymans, Iru Cai, Nicholas Chin.

Felix Singer has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/79746?usp=email )

Change subject: mainboard: add Dell Latitude E7240
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Patch Set 3:

(5 comments)

File src/mainboard/dell/e7240/Kconfig:

PS3: 
Add SPDX license header

File src/mainboard/dell/e7240/Kconfig.name:

PS3: 
Add SPDX license header

File src/mainboard/dell/e7240/Makefile.inc:

PS3: 
Makefiles use the type .mk now. Please rename.

File src/mainboard/dell/e7240/devicetree.cb:

PS3: 
Add SPDX license header

File src/mainboard/dell/e7240/dsdt.asl:

https://review.coreboot.org/c/coreboot/+/79746/comment/36a83a37_7174e3e1 :
PS3, Line 18: 	/* global NVS and variables. */
Seens superfluous, remove.