[PATCH] USB: Gonzo variable renaming in hub.c

As part of the cleanup effort, I wanted to name all the variables in hub.c
uniformly.  Currently there are different names for the same thing in
different routines, and the same names are used for different things --
it's impossible to keep things straight.  I also wanted to step away from
the deplorable practice of naming everything "dev".  It is not an
exaggeration that up until relatively recently one of the drivers (not the
hub driver, fortunately!) contained a line which looked basically like
this:

	dev->dev.dev = &intf->dev;

If you can make sense out of that, you're a better code reader than I am!

Ranting aside, this patch institutes the following name scheme for local
variables in hub.c:

	hub:		struct usb_hub
	hdev:		hub's corresponding struct usb_device
	hub_dev:	hub interface's embedded struct device
	udev:		general struct usb_device

There are a couple of genuine code changes hidden in there too.  Just
trivial things, like creating a local hub_dev variable for use in place of
&hub->intf->dev.