Fixes in_atomic stack-dump, when Mellanox module is loaded into the RT
Kernel.

Michael S. Tsirkin <mst@dev.mellanox.co.il> sayeth:
"Basically, if you just make spin_lock_irqsave (and spin_lock_irq) not disable
interrupts for non-raw spinlocks, I think all of infiniband will be fine without
changes."
Signed-off-by: Sven-Thorsten Dietrich <sven@thebigcorporation.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>