Add direct and dummy RPC caller

Adds two types of RPC caller for testing purposes.

Change-Id: Icba23859ed9db5dc96832b10a985dc670830c4ab
Signed-off-by: Julian Hall <julian.hall@arm.com>
diff --git a/components/rpc/direct/component.cmake b/components/rpc/direct/component.cmake
new file mode 100644
index 0000000..614c429
--- /dev/null
+++ b/components/rpc/direct/component.cmake
@@ -0,0 +1,14 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+if (NOT DEFINED TGT)
+	message(FATAL_ERROR "mandatory parameter TGT is not defined.")
+endif()
+
+target_sources(${TGT} PRIVATE
+	"${CMAKE_CURRENT_LIST_DIR}/direct_caller.c"
+	)
+