test(cactus): notifications support enabled in manifest

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I40f4809b158b4681ca8146b4359b99fae5855848
diff --git a/spm/cactus/plat/arm/tc0/fdts/cactus.dts b/spm/cactus/plat/arm/tc0/fdts/cactus.dts
index bcf9245..64daa3d 100644
--- a/spm/cactus/plat/arm/tc0/fdts/cactus.dts
+++ b/spm/cactus/plat/arm/tc0/fdts/cactus.dts
@@ -26,6 +26,7 @@
 	xlat-granule = <0>; /* 4KiB */
 	boot-order = <0>;
 	messaging-method = <3>; /* Direct messaging only */
+	notification-support; /* Support receipt of notifications. */
 	managed-exit; /* Managed exit supported */
 	run-time-model = <1>; /* Run to completion */