From: Russell King <redacted>
Date: Fri, 18 Sep 2015 10:54:55 +0100

Update the comment, and arrange for the only user of this function
to drop this refcount when disposing of a reference to it.

mdio_mux is not the only user of of_mdio_find_bus(), DSA uses it as
well.

So if anything this commit message is inaccurate.

I also wonder about this refcounting scheme.

If you are going to drop the inner device reference, then we take the
mdio bus returned from of_mdio_find_bus() what holds onto it and keeps
it from disappearing on us?

Don't we have to hold onto some reference count of some kind here?