UefiCpuPkg: Calculate DisplayFamily correctly

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4348



Per SDM:
DisplayFamily = Extended_Family_ID + Family_ID.
DisplayModelID = (Extended_Model_ID << 4) + Family_ID.
Correct the related code.

Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Cc: Mike Maslenkin <mike.maslenkin@gmail.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>