Add a document summarizing use of the LPC43xx USB hosts.
Add a document summarizing use of the LPC43xx USB hosts.

greatscottgadgets/greatfet,dominicgs/GreatFET-experimental,greatscottgadgets/greatfet,dominicgs/GreatFET-experimental,greatscottgadgets/greatfet,greatscottgadgets/greatfet,dominicgs/GreatFET-experimental