Update to accomodate for new tree layout

user-task.mk should be referred relative to top of the tree
as trusty/kernel/app/trusty/user-task.mk

Bug: 111521896
Change-Id: Ib4c2343795a578f8bda29460b71747a222a59f78

project/vexpress-a15-trusty.mk

diff --git a/project/vexpress-a15-trusty.mk b/project/vexpress-a15-trusty.mk
index cf8b08d..ff25bb9 100644
--- a/project/vexpress-a15-trusty.mk
+++ b/project/vexpress-a15-trusty.mk
@@ -67,4 +67,4 @@
 	trusty/user/app/sample/skel2\
 	trusty/user/app/sample/timer\
 
-EXTRA_BUILDRULES += app/trusty/user-tasks.mk
+EXTRA_BUILDRULES += trusty/kernel/app/trusty/user-tasks.mk