net: remove redundant NULL check in remove_xps_queue()

There are currently two paths that call remove_xps_queue():
1. __netif_set_xps_queue -> remove_xps_queue
2. clean_xps_maps -> remove_xps_queue_cpu -> remove_xps_queue
There is no need to check dev_maps in remove_xps_queue() because
dev_maps has been checked on these two paths.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20230724023735.2751602-1-shaozhengchao@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/dev.c

@@ -2384,8 +2384,7 @@ static bool remove_xps_queue(struct xps_dev_maps *dev_maps,
 	struct xps_map *map = NULL;
 	int pos;
 
-	if (dev_maps)
-		map = xmap_dereference(dev_maps->attr_map[tci]);
+	map = xmap_dereference(dev_maps->attr_map[tci]);
 	if (!map)
 		return false;