netif_set_xps_queue: make cpu mask const

virtio wants to pass in cpumask_of(cpu), make parameter
const to avoid build warnings.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -2264,11 +2264,12 @@ static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
 }
 
 #ifdef CONFIG_XPS
-extern int netif_set_xps_queue(struct net_device *dev, struct cpumask *mask,
+extern int netif_set_xps_queue(struct net_device *dev,
+			       const struct cpumask *mask,
 			       u16 index);
 #else
 static inline int netif_set_xps_queue(struct net_device *dev,
-				      struct cpumask *mask,
+				      const struct cpumask *mask,
 				      u16 index)
 {
 	return 0;

net/core/dev.c

@@ -1917,7 +1917,8 @@ static struct xps_map *expand_xps_map(struct xps_map *map,
 	return new_map;
 }
 
-int netif_set_xps_queue(struct net_device *dev, struct cpumask *mask, u16 index)
+int netif_set_xps_queue(struct net_device *dev, const struct cpumask *mask,
+			u16 index)
 {
 	struct xps_dev_maps *dev_maps, *new_dev_maps = NULL;
 	struct xps_map *map, *new_map;