Revert^2 "trusty: Mark vexpress-a15 target as 32-bit"

111773c30a16e55b1410b6f8c3b43055d9bc6696

Change-Id: I09f6b99b9117dbfd4c6781d9c2b3c67fc26f09f0
diff --git a/project/vexpress-a15-trusty.mk b/project/vexpress-a15-trusty.mk
index 2686874..475b30f 100644
--- a/project/vexpress-a15-trusty.mk
+++ b/project/vexpress-a15-trusty.mk
@@ -17,6 +17,8 @@
 
 TARGET := vexpress-a15
 
+KERNEL_32BIT := true
+
 #
 # GLOBAL definitions
 #