drivers/char: minor irq handler cleanups

- remove always-false tests

- don't overload 'irq' argument, pass data properly via dev_id

- remove pointless casts from void*

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index feac54e..874aaa0 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -1645,7 +1645,7 @@
 {
 	struct stlbrd *brdp = dev_id;
 
-	pr_debug("stl_intr(brdp=%p,irq=%d)\n", brdp, irq);
+	pr_debug("stl_intr(brdp=%p,irq=%d)\n", brdp, brdp->irq);
 
 	return IRQ_RETVAL((* brdp->isr)(brdp));
 }