staging: comedi: drivers: rename 'comedi_dev' in comedi_auto_config()

The struct comedi_device pointer in this file, and the rest of the
comedi subsystem, is typically called 'dev'. Rename the local variable
'comedi_dev' in comedi_auto_config() for consistency.

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>