Change in coreboot[master]: mb/intel/shadowmountain: Add bootblock and verstage code

[Angel Pons (Code Review)]

Attention is currently required from: V Sowmya, Martin Roth, Tim Wawrzynczak, Sugnan Prabhu S, Balaji Manigandan, Aamir Bohra.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/49479 )

Change subject: mb/intel/shadowmountain: Add bootblock and verstage code
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Patch Set 5: Code-Review+1

(1 comment)

File src/mainboard/intel/shadowmountain/Kconfig:

https://review.coreboot.org/c/coreboot/+/49479/comment/888b680a_6e2502e6 
PS5, Line 24: default y
Please drop the `default y`. Otherwise, the `!CHROMEOS` configuration doesn't get build-tested.