https://bugs.freedesktop.org/show_bug.cgi?id=107309
--- Comment #1 from Emil Velikov emil.l.velikov@gmail.com --- The message is harmless since Mesa falls back to use the DRM driver name.
That said, a slightly better (I'm obviously biased) solution has been on the list for ~month [1]. Just double-checked and pushed it to master.
[1] https://lists.freedesktop.org/archives/dri-devel/2018-June/181067.html