convert kaweth to use usb_reset_configuration()

For USB 3.0 it is necessary that all drivers use the standard
API to reset a configuration. This removes a home-grown
implementation.

Signed-off-by: Oliver Neukum <oliver@neukum.org>

Hi David,

please take this for the next merge window.

	Regards
		Oliver
Signed-off-by: David S. Miller <davem@davemloft.net>