Create efi-freebsd.h, which is safe to include from the FreeBSD context
(all of userland, except the small bits we share with edk2 and the
kernel). This defines anything that we need. At the moment, it just
includes NULL definitions.

Create efi-edk2.h, which is approximately ProcessorBind.h from edk2 that
we can include in FreeBSD compontents that are re-using edk2 components
(bits of the boot laoder, and libefi*). Update the efi_gid definitions
to match edk2 better. Add this file to badfiles.inc, since we can't
write it in a way that's compatible. This is copied from the old
efi-osdep.h.

Create a ProcessorBind.h that includes efi-edk2.h.

This mostly has to be done in one bigish commit since we can't easily
move things around they are so inter-related.

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