usb: wusbcore: remove excessive irqsave

wa_urb_dequeue() locks multiple spinlocks while disabling interrupts:

   spin_lock_irqsave(&lock1, flags);
   spin_lock_irqsave(&lock2, flags2);

Obviously there is no need for the second irqsave and "flags2" variable
since interrupts are disabled at that point. Remove the second irqsave:

   spin_lock_irqsave(&lock1, flags);
   spin_lock(&lock2);

and eliminate the flags2 variable.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>