Added MODULE_SRCS_FIRST to mention root object

While linking test-runner with original objects, linker
expecting the objects in the object-list in-order so object of
MODULE_SRCS_FIRST is placed as the first entry in the object list
otherwise module entry method was misplaced

Bug: 157916058
Change-Id: Ib2d61e00621e7f2d0110b69c51db620df3005e23
diff --git a/test-runner/arm64/rules.mk b/test-runner/arm64/rules.mk
index dd1ada0..3d2e67a 100644
--- a/test-runner/arm64/rules.mk
+++ b/test-runner/arm64/rules.mk
@@ -25,8 +25,10 @@
 MODULE_DEFINES += \
 	GIC_VERSION=$(GIC_VERSION) \
 
-MODULE_SRCS += \
+MODULE_SRCS_FIRST := \
 	$(LOCAL_DIR)/$(ARCH)/asm.S \
+
+MODULE_SRCS += \
 	$(LOCAL_DIR)/$(ARCH)/arch.c \
 	$(LOCAL_DIR)/$(ARCH)/boot.c \
 	$(LOCAL_DIR)/$(ARCH)/trusty_mem.c \