X64 arch needs to restart the MM dispatcher once MM entry point is registered, therefore set PcdRestartMmDispatcherOnceMmEntryRegistered to TRUE by default for X64 only. Cc: Ard Biesheuvel <ardb+tianocore@kernel.org> Cc: Sami Mujawar <sami.mujawar@arm.com> Cc: Ray Ni <ray.ni@intel.com> Cc: Jiaxin Wu <jiaxin.wu@intel.com> Signed-off-by: Wei6 Xu <wei6.xu@intel.com>