Change in coreboot[master]: soc/intel/skylake: Clean up serialio header file.

[build bot (Jenkins) (Code Review)]

build bot (Jenkins) has posted comments on this change. ( https://review.coreboot.org/19001 )

Change subject: soc/intel/skylake: Clean up serialio header file.
......................................................................

Patch Set 2: Verified+1

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/50701/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/6680/ : SUCCESS