USB: use "device number" instead of "address"

The USB stack historically has conflated device numbers (i.e., the
value of udev->devnum) with device addresses.  This is understandable,
because until recently the two values were always the same.

But with USB-3.0 they aren't the same, so we should start calling
these things by their correct names.  This patch (as1449b) changes many
of the references to "address" in the hub driver to "device number"
or "devnum".

The patch also removes some unnecessary or misleading comments.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Luben Tuikov <ltuikov@yahoo.com>
Reviewed-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>