hardirq: Make hardirq bits generic

There is no reason for per arch hardirq bits. Make them all generic

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130917183628.534494408@linutronix.de