phy/bitbang: missing MODULE_LICENSE

Missing MODULE_LICENSE(), loading this module taints the kernel.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/phy/mdio-bitbang.c b/drivers/net/phy/mdio-bitbang.c
index 8cd243d..2747b1f 100644
--- a/drivers/net/phy/mdio-bitbang.c
+++ b/drivers/net/phy/mdio-bitbang.c
@@ -185,3 +185,5 @@
 	module_put(ctrl->ops->owner);
 	kfree(bus);
 }
+
+MODULE_LICENSE("GPL");