Lara Spencer took to Instagram on Friday to reveal that her pet pooch Riva had been patiently waiting by the door all day for her son Duff to walk in.MORE: Lara Spencer shares then-and-now photos for heartfelt reason The teen was returning home to spend the weekend with his mom, the first time since he left to attend Southern Methodist University in Texas in August. WATCH: Lara Spencer and daughter perform jaw-dropping stunt in matching swimwear"Waiting by the door for Duff to get home from