Add support for hypervisor check on x86

Add ficl words for isvirtualized
and move ficl inb and outb words to ficl/x86/sysdep.c
so can be shared by i386 and amd64

MFC of r354043, r354055

Reviewed by: imp bdrewery
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22069