This patch converts most common hub diagnostics to use the
device model diagnostic macros ... not all, someone should
reduce the number of err() strings for "bogus hub" cases,
and ideally streamline some of the dozen or so "here's what's
special about this new hub" dbg() messages.

So the messages become more useful:  they id the port (and
implicitly the device) involved, using a kernel-wide standard
convention.  Size overhead is smaller too.

For folk running with USB debugging enabled, it also cuts
the useless chatter on connections by deleting the per-poll
success messages and a partial dup message when things change.
And it deletes a newish diagnostic on a (non-hub) unlink path.

It also makes Pete's new debounce message use the right
port number -- one-based, not zero-based.

My main issue with this patch is that it doesn't change
more messages, but it seems reasonable to merge it anyway.