scripts: use printf, not echo, where appropriate

printf has more universal behaviour, across various
implementations of sh, so it's better to use this.

Signed-off-by: Leah Rowe <leah@libreboot.org>

script/build/release/roms

@@ -97,7 +97,7 @@ make_archive()
 	cp "${builddir}"/* "${romdir}" || \
 	    err "make_archive: cannot copy ROM images directory -> ${romdir}"
 
-	echo ${target}
+	printf "%s\n" "${target}"
 
 	microcode_required="y"
 	. "config/coreboot/${target}/target.cfg"