The old versions of "Intel TDX Module v1.5 ABI Specification" contain
the definitions of all global metadata field IDs directly in a table.
However, the latest spec moves those definitions to a dedicated
'global_metadata.json' file as part of a new (separate) "Intel TDX
Module v1.5 ABI definitions" [1].
Update the comment to reflect this.
[1]: https://cdrdv2.intel.com/v1/dl/getContent/795381
Reported-by: Nikolay Borisov <nik.borisov@xxxxxxxx>
Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>