usb: uwb: use correct locking calls for rc data

The rc object's members can be accessed from both a timer and URB
callback.  Use spin_*_irq instead of spin_*_bh.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>