genirq: improve include files

Move the irq_desc related iterators out of irq.h, into irqnr.h, also
available via interrupt.h.

This way non-genirq (and even non-hardirq) architectures get the
common definitions and iterators.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 58ff4e7..72fcfcf 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -8,6 +8,7 @@
 #include <linux/preempt.h>
 #include <linux/cpumask.h>
 #include <linux/irqreturn.h>
+#include <linux/irqnr.h>
 #include <linux/hardirq.h>
 #include <linux/sched.h>
 #include <linux/irqflags.h>