MdeModulePkg/UniversalPayload: Add definition for extra info in payload

The payload is in ELF format per the universal payload spec.
UNIVERSAL_PAYLOAD_INFO_HEADER is stored in the ELF payload as a separate
section named ".upld_info".

Extra data needed by payload is stored in sections whose name starts
with ".upld.".

Signed-off-by: Ray Ni <ray.ni@intel.com>
Cc: Maurice Ma <maurice.ma@intel.com>
Cc: Guo Dong <guo.dong@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>

MdeModulePkg/Include/UniversalPayload/ExtraData.h

@@ -0,0 +1,28 @@
+/** @file
+
+  Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#ifndef EXTRA_DATA_H_
+#define EXTRA_DATA_H_
+
+extern GUID gUniversalPayloadExtraDataGuid;
+
+#pragma pack(1)
+
+typedef struct {
+  CHAR8                Identifier[16];
+  EFI_PHYSICAL_ADDRESS Base;
+  UINT64               Size;
+} UNIVERSAL_PAYLOAD_EXTRA_DATA_ENTRY;
+
+typedef struct {
+  UNIVERSAL_PAYLOAD_GENERIC_HEADER   PldHeader;
+  UINT32                             Count;
+  UNIVERSAL_PAYLOAD_EXTRA_DATA_ENTRY Entry[0];
+} UNIVERSAL_PAYLOAD_EXTRA_DATA;
+
+#pragma pack()
+
+#endif