net: txgbe: fix FDIR filter leak on remove

In the Linux kernel, the following vulnerability has been resolved: net: txgbe: fix FDIR filter leak on remove Perfect FDIR filters can be added while the interface is down and are kept on the software list for later restore. unregister_netdev() only calls ndo_stop when the device is up, so txgbe_fdir_filter_exit() in txgbe_close() is skipped in that case and the filters are leaked on driver remove. Free the filter list from txgbe_remove() as well.