x86/virt/tdx: Remove the auto-generated global metadata reader

All five TDX global metadata classes now have hand-maintained,
table-driven readers in tdx.c.  The only thing remaining in the
auto-generated tdx_global_metadata.c was the get_tdx_sys_info()
orchestrator that calls the per-class readers in order and prints
the module version once it has been read.

Move that orchestrator into tdx.c and delete the generated file
along with the unusual `#include "tdx_global_metadata.c"` that
spliced its contents into tdx.c at build time.  Behavior is
unchanged: the read order, the version print, and the error
propagation are preserved verbatim.

After this patch the entire TDX global metadata path -- the field
IDs, the C structures they populate, the per-field tables, and the
read code -- lives in tdx.h, asm/tdx_global_metadata.h, and tdx.c.
Adding a new field is now: extend the struct, add a TD_SYSINFO_MAP
entry naming the spec field next to the C member, done.  No
out-of-tree script and no regenerated source files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>