Change in coreboot[master]: soc/amd: Standardize guards on header files

[build bot (Jenkins) (Code Review)]

build bot (Jenkins) has posted comments on this change. ( https://review.coreboot.org/21073 )

Change subject: soc/amd: Standardize guards on header files
......................................................................

Patch Set 1: Verified+1

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/58779/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/14145/ : SUCCESS