for this and return NETDEV_TX_LOCKED when the spin lock fails.
The locking there should also properly protect against
set_multicast_list. Note that the use of NETIF_F_LLTX is deprecated.
- Dont use it for new drivers.
+ Don't use it for new drivers.
Context: Process with BHs disabled or BH (timer),
will be called with interrupts disabled by netconsole.