staging: comedi: usbduxsigma: tidy up the usb endpoint defines

Rename the defines so they have namespace associated with the driver.
Tidy up the defines.

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>