Besides being a little hard to parse through visually, this had its own
bug of inspecting st->st_mode to determine what to pass to devname(3),
which is only correct for st_rdev.

For st_dev, you're likely to be looking at files or directories and
attempting to assess what device they're located on, so the mode is
meaningless- we just have to assume that our filesystems are on
character devices and attempt to resolve st_dev as such.