Most animals have various microorganisms on their skin, each with its own smell (think of BO in humans). The sweet corn chip/popcorn smell is most likely caused by yeast or bacteria that live on your pup's paws. Some pet parents even enjoy the scent! There is no cause for alarm unless there is a greasy residue, powerful odor or excessive biting/licking - if that's the case, get in touch with your vet to figure out what is going on.