scripts: better handling of printf: stdout/stderr

in some cases, messages that should be considered errors
or warnings, were being written to the standard output,
rather than written as error messages.

also: one or two printf statements should specifically
avoid printing errors (to any file); in these cases,
stdout has been redirected to /dev/null

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

script/build/command/options

@@ -22,7 +22,7 @@ listitems()
 		# -e used because this is for files *or* directories
 		[ -e "${x}" ] || continue
 		[ "${x##*/}" = "build.list" ] && continue
-		printf "%s\n" "${x##*/}"
+		printf "%s\n" "${x##*/}" 2>/dev/null
 		items=0
 	done
 	return ${items}