vio: remove dangly makefile bits

The drivers are long gone but some config escaped the prune

Signed-off-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=57221


Signed-off-by: Jiri Kosina <jkosina@suse.cz>