usbd config file parse behaviour

[Sam Lawrance]

Hi,

usbd's present behaviour when reading usbd.conf is to scan from top to
bottom and use the first match.

What if it was changed to use the last, most specific match? That is,
the last match with the most of (product, vendor) specified.

The idea is that it makes it programmatically easy to add new entries to
the file - just place them at the end. Presently that won't work because
of the generic catch-all 
	device	"USB Device"
in the default usbd.conf.

I know this would be useful to me, so I'm just looking for somebody to
say "yeah maybe".

Cheers
Sam.