net: sfp: fix unbind

When unbinding, we don't correctly tear down the module state, leaving
(for example) the hwmon registration behind. Ensure everything is
properly removed by sending a remove event at unbind.

Fixes: 6b0da5c9c1 ("net: sfp: track upstream's attachment state in state machine")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/sfp.c

@@ -2294,6 +2294,10 @@ static int sfp_remove(struct platform_device *pdev)
 
 	sfp_unregister_socket(sfp->sfp_bus);
 
+	rtnl_lock();
+	sfp_sm_event(sfp, SFP_E_REMOVE);
+	rtnl_unlock();
+
 	return 0;
 }