fix kernel copy for arm

target/arm/Makefile

@@ -94,13 +94,13 @@ targethelp:
 endif
 
 kernel-strip:
+	@cp $(KERNEL) $(BUILD_DIR)/$(TARGET_KERNEL)
 ifeq ($(ADK_TARGET_SYSTEM_RASPBERRY_PI),y)
 ifeq ($(ADK_KERNEL_BCM2708_DT),y)
 	@echo adding DT trailer to kernel $(MAKE_TRACE)
+	-rm $(BUILD_DIR)/$(TARGET_KERNEL)
 	$(ADK_TOPDIR)/scripts/mkknlimg --dtok $(KERNEL) $(BUILD_DIR)/$(TARGET_KERNEL) $(MAKE_TRACE)
 endif
-else
-	@cp $(KERNEL) $(BUILD_DIR)/$(TARGET_KERNEL)
 endif
 
 kernel-install: kernel-strip