debian.package: mkdir -p to create whole tree

debian.package/Makefile

@@ -24,7 +24,7 @@ uefi-boot-metadata-collect-agent/boot/efi/secboot.cer: uefi-boot-metadata-collec
 	sudo chmod 755 $@
 
 uefi-boot-metadata-collect-agent/boot/efi:
-	mkdir -m 700 $@
+	mkdir -m 700 -p $@
 
 db.crt db.key:
 	openssl req -newkey rsa:4096 -nodes -keyout db.key -new -x509 -sha256 -days 3650 -subj "/CN=Nexedi's UEFI Signature Database key/" -out db.crt