trusty: Restore working trusty setup code and include trusty image in build

Change-Id: I081901e7df22f78dd9c4fc4c6bfad2aceb870a2d
Signed-off-by: Arve Hjønnevåg <arve@android.com>
diff --git a/services/spd/trusty/trusty.mk b/services/spd/trusty/trusty.mk
index beca875..920504c 100644
--- a/services/spd/trusty/trusty.mk
+++ b/services/spd/trusty/trusty.mk
@@ -8,3 +8,5 @@
 
 SPD_SOURCES		:=	services/spd/trusty/trusty.c		\
 				services/spd/trusty/trusty_helpers.S
+
+NEED_BL32		:=	yes