dt-bindings: net: dsa: qca8k: convert to YAML schema

Convert the qca8k bindings to YAML format.

Signed-off-by: Matthew Hagan <mnhagan88@gmail.com>
Co-developed-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>