staging: comedi: comedi_fops: remove use of DPRINTK

Use dev_dbg(), or pr_debug() when dev is not valid, instead of the
DPRINTK macro to output the comedi debugging information.

Remove the debug messages for allocation failures. The failure will
have already generated a message.

Reword the messages that include the dev->minor number. This number
will already be displayed as part of the dev_dbg() output.

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>