net: phy: mscc: Fix memory leak when using one step timestamping

In the Linux kernel, the following vulnerability has been resolved: net: phy: mscc: Fix memory leak when using one step timestamping Fix memory leak when running one-step timestamping. When running one-step sync timestamping, the HW is configured to insert the TX time into the frame, so there is no reason to keep the skb anymore. As in this case the HW will never generate an interrupt to say that the frame was timestamped, then the frame will never released. Fix this by freeing the frame in case of one-step timestamping.