ArmPkg/OpteeLib: Add APIs to communicate with OP-TEE

Add following APIs to communicate with OP-TEE pseudo/early TAs:
1. OpteeInit
2. OpteeOpenSession
3. OpteeCloseSession
4. OpteeInvokeFunc

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

ArmPkg/Library/OpteeLib/OpteeSmc.h

@@ -0,0 +1,53 @@
+/** @file
+  OP-TEE SMC header file.
+
+  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _OPTEE_SMC_H_
+#define _OPTEE_SMC_H_
+
+/* Returned in Arg0 only from Trusted OS functions */
+#define OPTEE_SMC_RETURN_OK                     0x0
+
+#define OPTEE_SMC_RETURN_FROM_RPC               0x32000003
+#define OPTEE_SMC_CALL_WITH_ARG                 0x32000004
+#define OPTEE_SMC_GET_SHARED_MEMORY_CONFIG      0xb2000007
+
+#define OPTEE_SMC_SHARED_MEMORY_CACHED          1
+
+#define OPTEE_SMC_RETURN_RPC_FOREIGN_INTERRUPT  0xffff0004
+
+#define OPTEE_MESSAGE_COMMAND_OPEN_SESSION      0
+#define OPTEE_MESSAGE_COMMAND_INVOKE_FUNCTION   1
+#define OPTEE_MESSAGE_COMMAND_CLOSE_SESSION     2
+
+#define OPTEE_MESSAGE_ATTRIBUTE_META            0x100
+
+#define OPTEE_LOGIN_PUBLIC                      0x0
+
+typedef struct {
+  UINTN    Base;
+  UINTN    Size;
+} OPTEE_SHARED_MEMORY_INFORMATION;
+
+//
+// UUID struct compliant with RFC4122 (network byte order).
+//
+typedef struct {
+  UINT32  Data1;
+  UINT16  Data2;
+  UINT16  Data3;
+  UINT8   Data4[8];
+} RFC4122_UUID;
+
+#endif