RDMA/ipoib: Remove unused declarations

There are some declarations without function definition, which are listed
as below:

1. ipoib_ib_tx_timer_func() has also been removed since
   commit 8966e28d ("IB/ipoib: Use NAPI in UD/TX flows")

2. ipoib_pkey_event() has been removed since
   commit ee1e2c82 ("IPoIB: Refresh paths instead of flushing them on
   SM change events")

3. ipoib_mcast_dev_down() has been removed since
   commit 988bd503 ("IPoIB: Fix memory leak of multicast group
   structures")

4. ipoib_pkey_open() has been removed since
   commit dd57c930 ("IB/ipoib: Avoid multicast join attempts with
   invalid P_key")

Remove these unused declarations.

Link: https://patch.msgid.link/r/20240818055702.79547-3-zhangzekun11@huawei.comSigned-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/ipoib/ipoib.h

@@ -509,12 +509,10 @@ struct net_device *ipoib_intf_alloc(struct ib_device *hca, u32 port,
 				    const char *format);
 int ipoib_intf_init(struct ib_device *hca, u32 port, const char *format,
 		    struct net_device *dev);
-void ipoib_ib_tx_timer_func(struct timer_list *t);
 void ipoib_ib_dev_flush_light(struct work_struct *work);
 void ipoib_ib_dev_flush_normal(struct work_struct *work);
 void ipoib_ib_dev_flush_heavy(struct work_struct *work);
 void ipoib_ib_tx_timeout_work(struct work_struct *work);
-void ipoib_pkey_event(struct work_struct *work);
 void ipoib_ib_dev_cleanup(struct net_device *dev);
 
 int ipoib_ib_dev_open_default(struct net_device *dev);
@@ -533,7 +531,6 @@ void ipoib_mcast_restart_task(struct work_struct *work);
 void ipoib_mcast_start_thread(struct net_device *dev);
 void ipoib_mcast_stop_thread(struct net_device *dev);
 
-void ipoib_mcast_dev_down(struct net_device *dev);
 void ipoib_mcast_dev_flush(struct net_device *dev);
 
 int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req);
@@ -610,7 +607,6 @@ int  ipoib_set_mode(struct net_device *dev, const char *buf);
 
 void ipoib_setup_common(struct net_device *dev);
 
-void ipoib_pkey_open(struct ipoib_dev_priv *priv);
 void ipoib_drain_cq(struct net_device *dev);
 
 void ipoib_set_ethtool_ops(struct net_device *dev);