Test: Add testcases for IRQ handling

This patch contains a test cases exercising the secure IRQ handling
feature of TF-M.

Details of the change:
 * Add documentation on the tests
 * Create new service which handles timer0 interrupts
 * Link timer0 driver structures to IRQ test service
 * Implement the testcases in the positive test suite, the new IRQ test
   service and in TFM_SP_CORE_TEST_2

Change-Id: If7e3d1b57eac4de9ff6e01f0b04efd04bc443545
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
diff --git a/test/test_services/CMakeLists.inc b/test/test_services/CMakeLists.inc
index d591ce6..cbfc572 100644
--- a/test/test_services/CMakeLists.inc
+++ b/test/test_services/CMakeLists.inc
@@ -38,6 +38,13 @@
 	list(APPEND ALL_SRC_C_S "${CORE_TEST_DIR}/tfm_core_test_2/tfm_ss_core_test_2.c")
 endif()
 
+if (NOT DEFINED ENABLE_IRQ_TEST_SERVICES)
+	message(FATAL_ERROR "Incomplete build configuration: ENABLE_IRQ_TEST_SERVICES is undefined. ")
+elseif(ENABLE_IRQ_TEST_SERVICES)
+	list(APPEND ALL_SRC_C_S
+		"${CORE_TEST_DIR}/tfm_irq_test_service_1/tfm_irq_test_service_1.c")
+endif()
+
 if (NOT DEFINED TFM_PARTITION_TEST_SECURE_SERVICES)
 	message(FATAL_ERROR "Incomplete build configuration: TFM_PARTITION_TEST_SECURE_SERVICES is undefined. ")
 elseif (TFM_PARTITION_TEST_SECURE_SERVICES)