UefiCpuPkg: Add LoongArch64 CPU Timer instance

Add the LoongArch64 CPU Timer instance to CpuTimerLib, using CPUCFG 0x4
and 0x5 for Stable Counter frequency.

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4734

Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Chao Li <lichao@loongson.cn>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>

UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf

@@ -1,10 +1,15 @@
 ## @file
 #  Base CPU Timer Library
 #
-#  Provides basic timer support using CPUID Leaf 0x15 XTAL frequency. The performance
+#  Provides basic timer support.
+#
+#  In x86, using CPUID Leaf 0x15 XTAL frequency. The performance
 #  counter features are provided by the processors time stamp counter.
 #
+#  In LoongArch64, using CPUCFG 0x4 and 0x5 for Stable Counter frequency.
+#
 #  Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2024, Loongson Technology Corporation Limited. All rights reserved.<BR>
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
 ##
@@ -18,10 +23,13 @@
   LIBRARY_CLASS                  = TimerLib
   MODULE_UNI_FILE                = BaseCpuTimerLib.uni
 
-[Sources]
+[Sources.IA32, Sources.X64]
   CpuTimerLib.c
   BaseCpuTimerLib.c
 
+[Sources.LoongArch64]
+  LoongArch64/CpuTimerLib.c
+
 [Packages]
   MdePkg/MdePkg.dec
   UefiCpuPkg/UefiCpuPkg.dec
@@ -31,5 +39,8 @@
   DebugLib
   PcdLib
 
+[LibraryClasses.LoongArch64]
+  SafeIntLib
+
 [Pcd]
   gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency  ## CONSUMES