net: phy: clean the sfp upstream if phy probing fails

In the Linux kernel, the following vulnerability has been resolved: net: phy: clean the sfp upstream if phy probing fails Sashiko reported that we don't call sfp_bus_del_upstream() in the probe failure path, so let's add it, otherwise the sfp-bus is left with a dangling 'upstream' field, that may be used later on during SFP events. This issue existed before the generic phylib sfp support, back when drivers were calling phy_sfp_probe themselves.