staging: comedi: dt2814: remove bad printk noise

This printk could spew a lot of noise while waiting for the ai conversion
to complete. Just remove it.

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>