llc: fix SAP refcount leak in llc_ui_autobind()

In the Linux kernel, the following vulnerability has been resolved: llc: fix SAP refcount leak in llc_ui_autobind() llc_ui_autobind() opens a SAP after choosing a dynamic LSAP. llc_sap_open() returns a reference owned by the caller, and llc_sap_add_socket() takes a second reference for the socket's membership in the SAP hash tables. llc_ui_bind() drops the caller's reference after adding the socket, but llc_ui_autobind() keeps it. When the socket is closed, llc_sap_remove_socket() releases only the socket reference, leaving the SAP on llc_sap_list with sk_count == 0. This is user-visible because repeated autobind and close cycles can consume all dynamic SAP values and make later autobinds fail with -EUSERS. Drop the caller's reference after a successful autobind, matching llc_ui_bind()'s ownership model.