Staging: comedi: fix printk issue in das16m1.c

This is a patch to the das16m1.c file that fixes up a printk
warning found by the checkpatch.pl tool.

converted printks to comedi_<level.
Removed an unnecessary printk statment.

Signed-off-by: Ravishankar Karkala Mallikarjunayya <ravishankar.km@greenturtles.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>