UefiCpuPkg/SmmCpuFeaturesLib: Clean up header file inclusion in SmmStm.c

UefiCpuPkg/SmmCpuFeaturesLib: Clean up header file inclusion in SmmStm.c

BZ# 4093: Abstract SmmCpuFeaturesLib for sharing common code

Remove the header files those are already included in
CpuFeatureLib.h.

Signed-off-by: Abner Chang <abner.chang@amd.com>
Cc: Abdul Lateef Attar <abdattar@amd.com>
Cc: Garrett Kirkendall <garrett.kirkendall@amd.com>
Cc: Paul Grimes <paul.grimes@amd.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>