__lpc_handle_xmit() has two bugs :

1) It can leak skbs in case TXSTATUS_ERROR is set

2) It can wake up txqueue while no slot was freed.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NRoland Stigge <stigge@antcom.de>
Tested-by: NRoland Stigge <stigge@antcom.de>
Cc: Kevin Wells <kevin.wells@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>