UefiCpuPkg/Include/Register/Msr/SkylakeMsr.h: Add new MSR name and keep old one.
UefiCpuPkg/Include/Register/Msr/SkylakeMsr.h: Add new MSR name and keep old one.

Changes includes:
  1. Change MSR name:
    1. MSR_SKYLAKE_SGXOWNER0 => MSR_SKYLAKE_SGXOWNEREPOCH0
    2. MSR_SKYLAKE_SGXOWNER1 => MSR_SKYLAKE_SGXOWNEREPOCH1
  2. Keep old MSR definition(MSR_SKYLAKE_SGXOWNER0/1) for compatibility
    1. Use below coding style to define old MSR
         #define MSR_SKYLAKE_SGXOWNER0  MSR_SKYLAKE_SGXOWNEREPOCH0

Cc: Michael D Kinney <fd20bc543a9f65bb633fac7d08a403c1f1c8eb6c@intel.com>
Cc: Ruiyu Ni <9fa3a6894a36bca79e6a72ad65af5a5702efecd1@intel.com>
Cc: Laszlo Ersek <7437296077edea1cb64451c122c4dac071f0cfbc@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <fa9eeec52367040ac98013bc4b2913db170588f8@intel.com>
Reviewed-by: Ruiyu Ni <9fa3a6894a36bca79e6a72ad65af5a5702efecd1@intel.com>
Acked-by: Laszlo Ersek <7437296077edea1cb64451c122c4dac071f0cfbc@redhat.com>

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