staging: wlan-ng: fix compilation for USB debugging

Fix compilation errors (remove references to 2 undefined fields in the
URB struct) when DEBUG_USB is defined for the wlan-ng driver.

Signed-off-by: Tim Collier <osdevtc@gmail.com>
Link: https://lore.kernel.org/r/20191025084126.9181-5-osdevtc@gmail.com


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