Eliminate pointless casts from void* in a few driver irq handlers.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/typhoon.c b/drivers/net/typhoon.c
index 72e5e9b..94ac586 100644
--- a/drivers/net/typhoon.c
+++ b/drivers/net/typhoon.c
@@ -1801,7 +1801,7 @@
 static irqreturn_t
 typhoon_interrupt(int irq, void *dev_instance)
 {
-	struct net_device *dev = (struct net_device *) dev_instance;
+	struct net_device *dev = dev_instance;
 	struct typhoon *tp = dev->priv;
 	void __iomem *ioaddr = tp->ioaddr;
 	u32 intr_status;