staging: comedi: usbdux: remove the usb_driver (*probe) noise

The dev_dbg() during the usb_driver (*probe) is just added noise.

The dev_err() when a usb_alloc_urb() fails is not necessary. The
allocation failure will have already output a message.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>