arch/x86/include: add missing license headers

These were all written as part of the coreboot project, so get
the standard coreboot license header.

Change-Id: I51e1e504b3bc7be2a00c9356d8775b87f2a1db5a
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12912
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
12 files changed