Your motherboard has no problems supporting an RX470. It just requires a PCIex16 slot. Although the GPU is PCIe v3.0, it is backward-compatible with your MB which has a PCIe v2.0. The GPU will run in PCIe2.0 speed though, but, is not at all noticeable.
As to your CPU (FX series) bottlenecking the performance of the RX470, there *might be*, there *might be not*. Really depends on the game you play, or how much you overclock the CPU. But there's a high chance, especially when playing CPU-intensive games (but probably in worst-case scenarios only).
I'd also look into your PSU though, if it has enough power for this upgrade.