ftgmac100: Restart MAC HW once

The interrupt handler may set the flag to reset the mac in the future,
but that flag is not cleared once the reset has occurred.

Fixes: 10cbd640 ("ftgmac100: Rework NAPI & interrupts handling")
Signed-off-by: Dylan Hung <dylan_hung@aspeedtech.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/faraday/ftgmac100.c

@@ -1337,6 +1337,7 @@ static int ftgmac100_poll(struct napi_struct *napi, int budget)
 	 */
 	if (unlikely(priv->need_mac_restart)) {
 		ftgmac100_start_hw(priv);
+		priv->need_mac_restart = false;
 
 		/* Re-enable "bad" interrupts */
 		iowrite32(FTGMAC100_INT_BAD,