bnxt_en: Remove locking around txr->dev_state

txr->dev_state was not consistently manipulated with the acquisition of
the per-queue lock, after further inspection the lock does not seem
necessary, either the value is read as BNXT_DEV_STATE_CLOSING or 0.

Reported-by: coverity (CID 1339583)
Fixes: c0c050c58d840 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Florian Fainelli <[e-mail]>
Acked-by: Michael Chan <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

···
 		for (i = 0; i < bp->tx_nr_rings; i++) {
 			txr = &bp->tx_ring[i];
 			txq = netdev_get_tx_queue(bp->dev, i);
-			__netif_tx_lock(txq, smp_processor_id());
 			txr->dev_state = BNXT_DEV_STATE_CLOSING;
-			__netif_tx_unlock(txq);
 		}
 	}
 	/* Stop all TX queues */