bridge: mcast: Constify 'group' argument in br_multicast_new_port_group()

The 'group' argument is not modified, so mark it as 'const'. It will
allow us to constify arguments of the callers of this function in future
patches.
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Acked-by: NNikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

net/bridge/br_multicast.c

@@ -1273,7 +1273,7 @@ br_multicast_new_group_src(struct net_bridge_port_group *pg, struct br_ip *src_i
 
 struct net_bridge_port_group *br_multicast_new_port_group(
 			struct net_bridge_port *port,
-			struct br_ip *group,
+			const struct br_ip *group,
 			struct net_bridge_port_group __rcu *next,
 			unsigned char flags,
 			const unsigned char *src,

net/bridge/br_private.h

@@ -941,7 +941,8 @@ br_mdb_ip_get(struct net_bridge *br, struct br_ip *dst);
 struct net_bridge_mdb_entry *
 br_multicast_new_group(struct net_bridge *br, struct br_ip *group);
 struct net_bridge_port_group *
-br_multicast_new_port_group(struct net_bridge_port *port, struct br_ip *group,
+br_multicast_new_port_group(struct net_bridge_port *port,
+			    const struct br_ip *group,
 			    struct net_bridge_port_group __rcu *next,
 			    unsigned char flags, const unsigned char *src,
 			    u8 filter_mode, u8 rt_protocol);