fix(runtime_services/ffa): dynamically calculate array size

This patch uses the ARRAY_SIZE() macro to calculate the number of
elements in the 'ffa_expected_partition_info' array instead of
hard-coding to '4'.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Change-Id: Iaa2d833a937d0d7f39a04c98a34e65f0dffe59d9
diff --git a/tftf/tests/runtime_services/secure_service/test_ffa_setup_and_discovery.c b/tftf/tests/runtime_services/secure_service/test_ffa_setup_and_discovery.c
index 9907284..e2929fc 100644
--- a/tftf/tests/runtime_services/secure_service/test_ffa_setup_and_discovery.c
+++ b/tftf/tests/runtime_services/secure_service/test_ffa_setup_and_discovery.c
@@ -352,7 +352,8 @@
 		return TEST_RESULT_FAIL;
 	}
 	if (!ffa_partition_info_helper(&mb, null_uuid,
-		ffa_expected_partition_info, 4)) {
+		ffa_expected_partition_info,
+		ARRAY_SIZE(ffa_expected_partition_info))) {
 		return TEST_RESULT_FAIL;
 	}