tftf: provide hvc conduit facility

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I3ad6e6767c2ca915f4a4fe8c5accc07e3e255387
diff --git a/include/lib/tftf_lib.h b/include/lib/tftf_lib.h
index 7f6786a..c3ad105 100644
--- a/include/lib/tftf_lib.h
+++ b/include/lib/tftf_lib.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -159,6 +159,15 @@
 smc_ret_values tftf_smc(const smc_args *args);
 
 /*
+ * Trigger an HVC call.
+ */
+typedef smc_args hvc_args;
+
+typedef smc_ret_values hvc_ret_values;
+
+hvc_ret_values tftf_hvc(const hvc_args *args);
+
+/*
  * Write a formatted string in the test output buffer.
  * Just like the standard libc's printf() function, the string produced is under
  * the control of a format string that specifies how subsequent arguments are