net: fec: ERR007885 Workaround for conventional TX

Activate TX hang workaround also in
fec_enet_txq_submit_skb() when TSO is not enabled.

Errata: ERR007885

Symptoms: NETDEV WATCHDOG: eth0 (fec): transmit queue 0 timed out

commit 37d6017b84f7 ("net: fec: Workaround for imx6sx enet tx hang when enable three queues")
There is a TDAR race condition for mutliQ when the software sets TDAR
and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles).
This will cause the udma_tx and udma_tx_arbiter state machines to hang.

So, the Workaround is checking TDAR status four time, if TDAR cleared by
    hardware and then write TDAR, otherwise don't set TDAR.

Fixes: 53bb20d1faba ("net: fec: add variable reg_desc_active to speed things up")
Signed-off-by: Mattias Barthel <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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