Fix a bug in irq_release() when searching interrupt list for the handler

to remove. The address of the pointer rather than the address of what
is pointed to was use to track the previous handler resulting in problems
when releasing a chained irq. (from John Ballance)

sys/arch/arm32/iomd/iomd_irqhandler.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: iomd_irqhandler.c,v 1.15 1997/10/14 11:06:01 mark Exp $	*/
+/*	$NetBSD: iomd_irqhandler.c,v 1.16 1997/11/07 01:04:51 mark Exp $	*/
 
 /*
  * Copyright (c) 1994-1996 Mark Brinicombe.
@@ -337,7 +337,7 @@ irq_release(irq, handler)
 	prehand = &irqhandlers[irq];
     
 	while (irqhand && handler != irqhand) {
-		prehand = &irqhand;
+		prehand = &irqhand->ih_next;
 		irqhand = irqhand->ih_next;
 	}