OvmfPkg: Update PlatformPei to support Tdx guest

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

OvmfPkg/PlatformPei is updated to support Tdx guest. There are below
major changes.
 - Set Tdx related PCDs
 - Publish Tdx RamRegions

In this patch there is another new function BuildPlatformInfoHob ().
This function builds EFI_HOB_PLATFORM_INFO which contains the
HostBridgeDevId. The hob is built in both Td guest and Non-Td guest.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@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: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

OvmfPkg/PlatformPei/FeatureControl.c

@@ -12,6 +12,7 @@
 #include <Library/QemuFwCfgLib.h>
 #include <Ppi/MpServices.h>
 #include <Register/ArchitecturalMsr.h>
+#include <IndustryStandard/Tdx.h>
 
 #include "Platform.h"
 
@@ -37,7 +38,11 @@ WriteFeatureControl (
   IN OUT VOID  *WorkSpace
   )
 {
-  AsmWriteMsr64 (MSR_IA32_FEATURE_CONTROL, mFeatureControlValue);
+  if (TdIsEnabled ()) {
+    TdVmCall (TDVMCALL_WRMSR, (UINT64)MSR_IA32_FEATURE_CONTROL, mFeatureControlValue, 0, 0, 0);
+  } else {
+    AsmWriteMsr64 (MSR_IA32_FEATURE_CONTROL, mFeatureControlValue);
+  }
 }
 
 /**