tipc: Remove unused declaration tipc_link_build_bc_sync_msg()

Commit 52666986 ("tipc: let broadcast packet reception use new link receive function")
declared but never implemented this.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230807142926.45752-1-yuehaibing@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/tipc/link.h

@@ -148,8 +148,6 @@ int tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked, u16 gap,
 			 struct tipc_gap_ack_blks *ga,
 			 struct sk_buff_head *xmitq,
 			 struct sk_buff_head *retrq);
-void tipc_link_build_bc_sync_msg(struct tipc_link *l,
-				 struct sk_buff_head *xmitq);
 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr);
 int tipc_link_bc_sync_rcv(struct tipc_link *l,   struct tipc_msg *hdr,
 			  struct sk_buff_head *xmitq);