USB: ldusb: remove custom dbg_info() macro

We want to get rid of CONFIG_USB_DEBUG, so remove the reliance of the
ldusb driver on it.  Don't use the custom macro, or a special module
parameter, instead, rely on the in-kernel dynamic debugging
infrastructure, which is much easier to use, and consistant across the
whole kernel.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>