IntelFsp2Pkg: SecFspSecPlatformLibNull support for X64

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3893
1.Added SecFspSecPlatformLibNull support for X64.
2.Added X64 support to IntelFsp2Pkg.dsc.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Ashraf Ali S <ashraf.ali.s@intel.com>
Signed-off-by: Ted Kuo <ted.kuo@intel.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>

IntelFsp2Pkg/Library/SecFspSecPlatformLibNull/X64/SecCarInit.nasm

@@ -0,0 +1,40 @@
+;; @file
+;  SEC CAR function
+;
+; Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;;
+
+;
+; Define assembler characteristics
+;
+
+%macro RET_RSI 0
+
+  movd    rsi, mm7                      ; move ReturnAddress from MM7 to RSI
+  jmp     rsi
+
+%endmacro
+
+SECTION .text
+
+;-----------------------------------------------------------------------------
+;
+;  Section:     SecCarInit
+;
+;  Description: This function initializes the Cache for Data, Stack, and Code
+;
+;-----------------------------------------------------------------------------
+global ASM_PFX(SecCarInit)
+ASM_PFX(SecCarInit):
+
+  ;
+  ; Set up CAR
+  ;
+
+  xor    rax, rax
+
+SecCarInitExit:
+
+  RET_RSI
+