net/phy: Remove return value for void function

This was caught when using a spatch (aka. coccinelle) script
written by Joe Perches.

Cc: Joe Perches <joe@perches.com>
Signed-off-by: Shruti Kanetkar <Shruti@Freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index 11f3481..180c494 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -249,8 +249,7 @@
 
 static void __exit smsc_exit(void)
 {
-	return phy_drivers_unregister(smsc_phy_driver,
-		ARRAY_SIZE(smsc_phy_driver));
+	phy_drivers_unregister(smsc_phy_driver, ARRAY_SIZE(smsc_phy_driver));
 }
 
 MODULE_DESCRIPTION("SMSC PHY driver");