net: gve: remove duplicated allowed

fix the WARNING of Possible repeated word: 'allowed'
Signed-off-by: Daode Huang <huangdaode@huawei.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/google/gve/gve_ethtool.c

@@ -388,7 +388,7 @@ static int gve_set_channels(struct net_device *netdev,
 
 	gve_get_channels(netdev, &old_settings);
 
-	/* Changing combined is not allowed allowed */
+	/* Changing combined is not allowed */
 	if (cmd->combined_count != old_settings.combined_count)
 		return -EINVAL;