staging: comedi: ni_atmio: remove board attach noise

Remove the printk messages in the (*attach) of this driver. These are
just added noise.

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>