phy: mdio-cavium: Add missing MODULE_* annotations.

BugLink: http://bugs.launchpad.net/bugs/1562968

When the code was factored out of mdio-octeon.c, the
MODULE_DESCRIPTION, MODULE_AUTHOR and MODULE_LICENSE annotations were
inadvertently omitted.  Restore them so that we don't get kernel taint
warnings upon module loading.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 7091f01e)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/net/phy/mdio-cavium.c

@@ -147,3 +147,7 @@ int cavium_mdiobus_write(struct mii_bus *bus, int phy_id, int regnum, u16 val)
 	return 0;
 }
 EXPORT_SYMBOL(cavium_mdiobus_write);
+
+MODULE_DESCRIPTION("Common code for OCTEON and Thunder MDIO bus drivers");
+MODULE_AUTHOR("David Daney");
+MODULE_LICENSE("GPL");