libsp: Add sp_rxtx.h mock implementation

Enabling the validation of SP layer RXTX calls from other SP layer
modules or from user code.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: Ia08d5fc0e07a0f18a29c2cc3d8b30c63286954a8
diff --git a/components/messaging/ffa/libsp/tests.cmake b/components/messaging/ffa/libsp/tests.cmake
index bfa994f..200f8c0 100644
--- a/components/messaging/ffa/libsp/tests.cmake
+++ b/components/messaging/ffa/libsp/tests.cmake
@@ -70,3 +70,15 @@
 	COMPILE_DEFINITIONS
 		-DARM64
 )
+
+unit_test_add_suite(
+	NAME libsp_mock_sp_rxtx
+	SOURCES
+		${CMAKE_CURRENT_LIST_DIR}/test/test_mock_sp_rxtx.cpp
+		${CMAKE_CURRENT_LIST_DIR}/test/mock_sp_rxtx.cpp
+	INCLUDE_DIRECTORIES
+		${CMAKE_CURRENT_LIST_DIR}/include/
+		${PROJECT_PATH}/components/common/utils/include
+	COMPILE_DEFINITIONS
+		-DARM64
+)