sfc: don't call tx_remove if there isn't one

EF100 won't have an efx->type->tx_remove method, because there's
 nothing for it to do.  So make the call conditional.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed