staging: comedi: usbdux: remove the usb endpoint defines

The endpoint defines are each only used in one place and don't help
clarify the code. Remove the defines and just open code the values.

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