plat: marvell: armada: a3k: Do not modify $(WTMI_MULTI_IMG)

Rather create a temporary copy in $(BUILD_PLAT) and modify only copy.
Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I256c029106ea6f69faa086fc4e5bee9f68cd257f

plat/marvell/armada/a3k/common/a3700_common.mk

@@ -156,8 +156,9 @@ ifeq ($(MARVELL_SECURE_BOOT),1)
 	@echo -e "\n\t=======================================================\n";
 	@echo -e "\t  Secure boot. Encrypting wtmi and boot-image \n";
 	@echo -e "\t=======================================================\n";
-	@truncate -s %16 $(WTMI_MULTI_IMG)
-	@openssl enc -aes-256-cbc -e -in $(WTMI_MULTI_IMG) \
+	@cp $(WTMI_MULTI_IMG) $(BUILD_PLAT)/wtmi-align.bin
+	@truncate -s %16 $(BUILD_PLAT)/wtmi-align.bin
+	@openssl enc -aes-256-cbc -e -in $(BUILD_PLAT)/wtmi-align.bin \
 	-out $(WTMI_ENC_IMG) \
 	-K `cat $(IMAGESPATH)/aes-256.txt` -nosalt \
 	-iv `cat $(IMAGESPATH)/iv.txt` -p