staging: comedi: unionxx5: tidy up some dev_{level} messages

Remove the "comedi%d:" prefix from the dev_{level} messages. This previx
will already be displayed.

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>