Hor-Aha (or Aha or Horus Aha) is considered the second pharaoh of the First Dynasty of Egypt by some Egyptologists, others consider him the first one and corresponding to Menes. He lived around the 31st century BC and is thought to have had a long reign.
The short answer is that we don't know for certain. Our understanding of the early evolution of the Egyptian pantheon is limited by the paucity of early texts. What we can say is neatly summarised by Richard H. Wilkinson in his ambitiously titled The Complete Gods and Goddesses of Ancient Egypt:
Horus was one of the earliest Egyptian deities. His name is attested from the beginning of the Dynastic Period and it is probable that early falcon deities such as that shown restraining the 'marsh dwellers' on the Narmer Palette represent this same god.
- Richard H. Wilkinson: The Complete Gods and Goddesses of Ancient Egypt, Thames & Hudson, 2003, p200
If the falcon deity depicted on the Narmer Palette is indeed Horus, then the deity does pre-date Hor-Aha.