usbnet: Transfer of maintainership

Somebody has to do it, however unfortunate be the cause.

Signed-off-by: Oliver Neukum <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

MAINTAINERS

···
 F:	drivers/usb/host/uhci*
 
 USB "USBNET" DRIVER FRAMEWORK
-M:	David Brownell <[e-mail]>
+M:	Oliver Neukum <[e-mail]>
 L:	[e-mail]
 W:	http://www.linux-usb.org/usbnet
 S:	Maintained