drivers/net: Remove casts of void *

Unnecessary casts of void * clutter the code.

These are the remainder casts after several specific
patches to remove netdev_priv and dev_priv.

Done via coccinelle script (and a little editing):

$ cat cast_void_pointer.cocci
@@
type T;
T *pt;
void *pv;
@@

- pt = (T *)pv;
+ pt = pv;

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-By: Chris Snook <chris.snook@gmail.com>
Acked-by: Jon Mason <jdmason@kudzu.us>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David Dillow <dave@thedillows.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tokenring/madgemc.c

@@ -418,7 +418,7 @@ static irqreturn_t madgemc_interrupt(int irq, void *dev_id)
 		return IRQ_NONE;
 	}
 
-	dev = (struct net_device *)dev_id;
+	dev = dev_id;
 
 	/* Make sure its really us. -- the Madge way */
 	pending = inb(dev->base_addr + MC_CONTROL_REG0);