x86_64: Turn on 64-bit core registers initialization.
x86_64: Turn on 64-bit core registers initialization.

This enables 64-bit core registers initialization for x86_64.
The backend update with 64-bit temp support is in progress.

Change-Id: If7c9a62c1145f81050adda86f2beed427220baa2
Signed-off-by: Chao-ying Fu <c078ef5f1329117a5e656c5fe26c03054f1bcf45@intel.com>
Signed-off-by: Dmitry Petrochenko <3a759f8171aff1439cfbcab3315fbbed4c685172@intel.com>
Signed-off-by: Serguei Katkov <53c1eb3349c33a81de4c7fece05dd168a3eb410e@intel.com>
Signed-off-by: Mark Mendell <5bb071d19b5f52f0c911305e14ccfad9a9b022c3@intel.com>

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst