MdePkg: Introduce basic Tdx functions in BaseLib

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

Introduce basic Tdx functions in BaseLib:
 - TdCall ()
 - TdVmCall ()
 - TdIsEnabled ()

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

MdePkg/Library/BaseLib/BaseLib.inf

@@ -210,6 +210,7 @@
   X86RdRand.c
   X86PatchInstruction.c
   X86SpeculationBarrier.c
+  IntelTdxNull.c
 
 [Sources.X64]
   X64/Thunk16.nasm
@@ -293,6 +294,9 @@
   X64/ReadCr0.nasm| MSFT
   X64/ReadEflags.nasm| MSFT
 
+  X64/TdCall.nasm
+  X64/TdVmcall.nasm
+  X64/TdProbe.c
 
   X64/Non-existing.c
   Math64.c