staging: comedi: s626: remove private DEBUG macro

The private DEBUG macro defined in this driver outputs a lot
of function tracing noise. This information might be useful
when first developing the driver but should not be in the
mainlined code.

If any of this is needed in the future it should be added back
using the proper dev_printk interface.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>