Fix make etcd image failed

Signed-off-by: kkkkun <scuzk373x@gmail.com>

cluster/images/etcd/Makefile

@@ -180,9 +180,9 @@ else
 
 	# Add this ENV variable in order to workaround an unsupported arch blocker
 	# On arm (which is 32-bit), it can't handle >1GB data in-memory
-	ifeq ($(ARCH),arm)
+        ifeq ($(ARCH),arm)
 		cd $(TEMP_DIR) && echo "ENV ETCD_UNSUPPORTED_ARCH=$(ARCH)" >> $(DOCKERFILE)
-	endif
+        endif
 endif
 
 	docker run --rm --privileged multiarch/qemu-user-static:$(QEMUVERSION) --reset -p yes