Staging: comedi: addi-data: replace printk() with dev_err() in hwdrv_apci1564.c

There were a small handful of printk() calls in hwdrv_apci1564.c.  It is
generally better to use dev_err() for error messages instead, so I
switched all the printk() calls out, as well as cleaned up the error
strings.

Signed-off-by: Chase Southwood <chase.southwood@yahoo.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>