These source files have been unused for the entire lifecycle of the
project. They're a hold-over from Citra and only add to the build time
of the project, so they can be removed.

There's also likely no way this would ever work in yuzu in its current
form without revamping quite a bit of it, given how different the GPU on
the Switch is compared to the 3DS.

Avoids unwanted implicit conversions. Thankfully, given the large amount
of cleanup in past PRs, only this tiny amount is left over to cover.

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.