Although at this point, its still cosmetic, but the mortar joints on these steps should be cleaned up and re-pointed. Left in this condition, moisture will get in there and create more damage. In the winter months, moisture can get in there, freeze, expand and could cause cracking of the brick/mortar. One thing that could prevent this from happening is sealing the mortar joints. Various inexpensive sealants can be found at your local home improvement stores.