arch-x86: consistent style of comments in system files

Change-Id: I9f208819b8c1a5c46a77262eb533bb47adb2b905
Reviewed-on: https://gem5-review.googlesource.com/7701
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>
2 files changed