Change in coreboot[master]: src/include: Add guards on all header files

[build bot (Jenkins) (Code Review)]

build bot (Jenkins) has posted comments on this change. ( https://review.coreboot.org/20734 )

Change subject: src/include: Add guards on all header files
......................................................................

Patch Set 3: Verified+1

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/58074/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/13507/ : SUCCESS