arch-x86: Specialize LTR for 64 bit mode.

Like LDT descriptors, the TR descriptors are 128 bits in 64 bit mode,
and only 64 bits in other modes.

Change-Id: Iecfab8c5a90a8bfe0dff86880bc8f88c082ddc0e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55886
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
2 files changed