plat: tc0: enable managed exit for primary cactus

Change-Id: Ica641c18868dd040f78fe4dce5964f1c4154b3e5
Signed-off-by: Arunachalam Ganapathy <arunachalam.ganapathy@arm.com>
diff --git a/spm/cactus/plat/arm/tc0/fdts/cactus.dts b/spm/cactus/plat/arm/tc0/fdts/cactus.dts
index bd7c546..eaca735 100644
--- a/spm/cactus/plat/arm/tc0/fdts/cactus.dts
+++ b/spm/cactus/plat/arm/tc0/fdts/cactus.dts
@@ -25,7 +25,7 @@
 	entrypoint-offset = <0x00001000>;
 	xlat-granule = <0>; /* 4KiB */
 	boot-order = <0>;
-	messaging-method = <0>; /* Direct messaging only */
+	messaging-method = <3>; /* Direct messaging with managed exit */
 	run-time-model = <1>; /* Run to completion */
 
 	/* Boot protocol */