genirq: Provide default irq init flags

Arch code sets it's own irq_desc.status flags right after boot and for
dynamically allocated interrupts. That might involve iterating over a
huge array.

Allow ARCH_IRQ_INIT_FLAGS to set separate flags aside of IRQ_DISABLED
which is the default.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

kernel/irq/chip.c

@@ -31,7 +31,7 @@ static void dynamic_irq_init_x(unsigned int irq, bool keep_chip_data)
 
 	/* Ensure we don't have left over values from a previous use of this irq */
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	desc->status = IRQ_DISABLED;
+	desc->status = IRQ_DEFAULT_INIT_FLAGS;
 	desc->irq_data.chip = &no_irq_chip;
 	desc->handle_irq = handle_bad_irq;
 	desc->depth = 1;