tg3: Fix num of RX queues being reported by ethtool

Using num_online_cpus() to report number of queues is actually not
correct, as reported by Michael[1].

netif_get_num_default_rss_queues() was used to replace num_online_cpus()
in the past, but tg3 ethtool callbacks didn't get converted. Doing it
now.

Link: https://lore.kernel.org/all/CACKFLim7ruspmqvjr6bNRq5Z_XXVk3vVaLZOons7kMCzsEG23A@mail.gmail.com/#t [1]

Signed-off-by: Breno Leitao <[email protected]>
Suggested-by: Michael Chan <[email protected]>
Reviewed-by: Michael Chan <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: leitao

drivers/net/ethernet/broadcom/tg3.c

@@ -12729,7 +12729,7 @@ static u32 tg3_get_rx_ring_count(struct net_device *dev)
 	if (netif_running(tp->dev))
 		return tp->rxq_cnt;
 
-	return min(num_online_cpus(), TG3_RSS_MAX_NUM_QS);
+	return min_t(u32, netif_get_num_default_rss_queues(), tp->rxq_max);
 }
 
 static u32 tg3_get_rxfh_indir_size(struct net_device *dev)