UefiCpuPkg/RegisterCpuFeaturesLib: Define Index to UINT64

UefiCpuPkg/RegisterCpuFeaturesLib: Define Index to UINT64

The input parameter Index of PreSmmCpuRegisterTableWrite() and
CpuRegisterTableWrite() is defined as UINT32. Index is MSR/MMIO address that
will be saved in CPU register table. UINT32 blocks the MMIO address > 4GB.

This fix is to define Index to UINT64 instead of UINT32.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>