Later edit: I think you have to compile the whole Linux kernel with the patched amdgpu driver. The GitHub repository for it is linked in the article: https://github.com/mkopec/linux

Edit: I shouldn't comment before reading the article.. This whole comment is irrelevant. Keeping it up for posterity.

End-users generally use the amdgpu driver in the Linux kernel. When it's ready, it'll be merged into the kernel and your next kernel update will have it. If you're on a gaming-targeted distro, they usually get kernel updates pretty fast, so you won't have to wait long after it's ready.

Or TL;DR: do nothing, keep your system up to date, you'll get it eventually!