[TG3]: TSO workaround fixes.

1.  Add race condition check after netif_stop_queue().  tg3_tx() runs
    without netif_tx_lock and can race with tg3_start_xmit_dma_bug() ->
    tg3_tso_bug().

2.  Firmware TSO in 5703/5704/5705 also have the same TSO limitation,
    i.e. they cannot handle TSO headers bigger than 80 bytes.  Rename
    TG3_FL2_HW_TSO_1_BUG to TG3_FL2_TSO_BUG and set this flag on
    these chips as well.

3.  Update version to 3.74.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>