Added libwolfboot to nrf53 app build

Author: danielinux

test-app/Makefile

@@ -215,6 +215,7 @@ ifeq ($(TARGET),stm32u5)
 endif
 
 ifeq ($(TARGET),nrf5340_net)
+  APP_OBJS:=app_$(TARGET).o ../test-app/libwolfboot.o
   LSCRIPT_TEMPLATE=ARM-nrf5340_net.ld
 endif