SecurityPkg: Add definition of EFI_CC_EVENT_HOB_GUID

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3853

EFI_CC_EVENT_HOB_GUID is the global ID of a GUIDed HOB used to pass
TDX_DIGEST_VALUE from SEC to a DXE Driver ( This DXE driver will
be introduced in the following commit in this patch-sets ). In that
DXE driver this GUIDed HOB will be parsed and the TDX_DIGEST_VALUE
then will be extracted. After that a EFI_CC_EVENT will be created
based on it.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

SecurityPkg/Include/Guid/CcEventHob.h

@@ -0,0 +1,22 @@
+/** @file
+  Defines the HOB GUID used to pass a CC_EVENT from SEC to
+  a CC DXE Driver. A GUIDed HOB is generated for each measurement
+  made in the SEC Phase.
+
+Copyright (c) 2021 - 2022, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef CC_EVENT_HOB_H_
+#define CC_EVENT_HOB_H_
+
+//
+// The Global ID of a GUIDed HOB used to pass a CC_EVENT from SEC to a CC DXE Driver.
+//
+#define EFI_CC_EVENT_HOB_GUID \
+  { 0x20f8fd36, 0x6d00, 0x40fb, { 0xb7, 0x04, 0xd1, 0x2c, 0x15, 0x3c, 0x62, 0xeb } }
+
+extern EFI_GUID  gCcEventEntryHobGuid;
+
+#endif