Resolve USB driver identification conflict.

Reported by:	Anish Mistry <amistry@am-productions.biz>
MFC after:	1 week
Regenerate usb.conf .

MFC after:	1 week
Eliminate fdt_data_verify(). The verification it proceed is wrong
disallowing us to encode 64-bit register numbers.

Discussed with:	nwhitehorn, andrew