platform/x86/intel/vsec.h: Move to include/linux

Some drivers outside of PDX86 need access to the vsec header. Move it to
include/linux to make it easier to include.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20240725122346.4063913-2-michael.j.ruhl@intel.com


Signed-off-by: Hans de Goede <hdegoede@redhat.com>