UefiCpuPkg: Add dynamic type for PcdCpuMaxLogicalProcessorNumber

UefiCpuPkg: Add dynamic type for PcdCpuMaxLogicalProcessorNumber

Currently, PcdCpuMaxLogicalProcessorNumber only supports fixed type. There are
some requests on this PCD to support dynamic type also. For example, platform
may dynamically set this PCD to actual processor count to save memory or improve
boot performance.

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>