OvmfPkg: Refactor ProcessHobList

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4243

ProcessHobList once was implemented in PlatformInitLib and it walks thru
TdHob list and accept un-accepted memories.

This patch moves the codes to SecTdxHelperLib and rename ProcessHobList
as TdxHelperProcessTdHob

After TdxHelperProcessTdHob is introduced, below changes are applied:
 - Call TdxHelperProcessTdHob instead of ProcessHobList in SecMain.c
   (in both OvmfPkgX64/Sec and IntelTdx/Sec).
 - Delete the duplicated codes in PlatformInitLib

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

OvmfPkg/Include/Library/PlatformInitLib.h

@@ -210,23 +210,6 @@ PlatformMaxCpuCountInitialization (
   IN OUT EFI_HOB_PLATFORM_INFO  *PlatformInfoHob
   );
 
-/**
-  In Tdx guest, some information need to be passed from host VMM to guest
-  firmware. For example, the memory resource, etc. These information are
-  prepared by host VMM and put in HobList which is described in TdxMetadata.
-
-  Information in HobList is treated as external input. From the security
-  perspective before it is consumed, it should be validated.
-
-  @retval   EFI_SUCCESS   Successfully process the hoblist
-  @retval   Others        Other error as indicated
-**/
-EFI_STATUS
-EFIAPI
-ProcessTdxHobList (
-  VOID
-  );
-
 /**
   In Tdx guest, the system memory is passed in TdHob by host VMM. So
   the major task of PlatformTdxPublishRamRegions is to walk thru the