illumos gate

Since the Westmere microarchitecture, Intel CPUs have had the capability to run with the "Unrestricted Guest", where VMX guests are able to run in real mode (allowing for guest software such as boot roms). FreeBSD bhyve supported older CPUs by loading the OS directly with helpers such as grub2-bhyve, where the guest is started directly in protected mode. Since illumos bhyve has never shipped any of those helpers, and already enforces availability of Unrestricted Guest mode, we should automatically enable it and removed that complication from bhyve.