src: Consolidate x86_64 support Kconfig

Introduce `USE_EXP_X86_64_SUPPORT` in `src/arch/x86/Kconfig` and guard
it with `HAVE_EXP_X86_64_SUPPORT`. Replace the per-CPU implementations
of the same functionality with the newly-added Kconfig options. Update
documentation and the config file for QEMU accordingly.

Change-Id: I550216fd2a8323342d6b605306b0b95ffd5dcd1c
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55760
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

0 files changed, 0 insertions, 0 deletions