x86/head64.c: Early update ucode in 64-bit

This updates ucode on BSP in 64-bit mode. Paging and virtual address are
working now.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1356075872-3054-11-git-send-email-fenghua.yu@intel.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>