x86/boot: Switch to new Intel CPU model defines

New CPU #defines encode vendor and family as well as model but
boot code doesn't have all the infrastructure to use them. Hard
code the one CPU model number used here.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240520224620.9480-35-tony.luck%40intel.com