Staging: aten2011: remove DPRINTK macro

Convert to use the dbg() macro we already have in the usb-serial layer.
This also turns off the default for the driver to spit out all of the
debug messages, now it is controlled by the module parameter.

Cc: Russell Lang <gsview@ghostgum.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>