lib.sh mktarball: cleaner if statement

i also removed that printf, because the path it prints is
actually wrong sometimes; in the recent re-write of vendor.sh,
it prints the correct path instead

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

include/lib.sh

@@ -170,9 +170,9 @@ mkrom_tarball()
 
 mktarball()
 {
-	[ "${2%/*}" = "$2" ] || \
+	if [ "${2%/*}" != "$2" ]; then
 		mkdir -p "${2%/*}" || $err "mk, !mkdir -p \"${2%/*}\""
-	printf "\nCreating archive: %s\n\n" "$2"
+	fi
 	tar -c "$1" | xz -T$XBMK_THREADS -9e > "$2" || $err "mktarball 2, $1"
 }