proc: fixup irq iterator

There is no need for irq_desc here. Even for sparse_irq we can
handle this clever in for_each_irq_nr().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 31632aa..0618fb3 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -27,6 +27,9 @@
 	     irq > 0; irq--, desc--)
 #endif
 
+#define for_each_irq_nr(irq)			\
+	for (irq = 0; irq < nr_irqs; irq++)
+
 #ifndef CONFIG_S390
 
 #include <linux/linkage.h>