arch/x86/postcar: Add x86_64 support

* Add support for loading GDT on x86_64.
* Add x86_64 assembly code to do the same as the x86_32 code.
* Separate x86_32 and x86_64 code.

Tested on qemu x86_32 and x86_64 using additional MTRRs.
Tested on Lenovo T410 with additional x86_64 patches.

Change-Id: I1c190627f5f0ed6f82738cb99423892382899d7b
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/30500
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions