staging: comedi: dmm32at: convert a printk(KERN_ERR to a dev->err()

Convert this printk message to a dev_err() message.

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>