wireless/bluetooth: Soften use of enter_critical_sectino() which is a...

wireless/bluetooth:  Soften use of enter_critical_sectino() which is a performance hog in SMP configurations.  Replace with spin_lock_irqsave() in most cases.  That is the same for single core CPUs, but much more efficient in SMP configurations.  And better, repace with sched_lock() if there is really no necessity to disable interrupts too.