USB: media: lirc: igorplugusb: remove CONFIG_USB_DEBUG support

The config option is gone, so port the driver over to using the dynamic
debug infrastructure instead, like all other USB drivers.

Cc: Jarod Wilson <jarod@wilsonet.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Cc: Matina Maria Trompouki <mtrompou@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>