net/core: Use RCU_INIT_POINTER(x, NULL) in netpoll.c

This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure
is carried out before storing a pointer to that structure.
And in the case of the NULL pointer, there is no structure to initialize.
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)

Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -809,7 +809,7 @@ void __netpoll_cleanup(struct netpoll *np)
 		if (ops->ndo_netpoll_cleanup)
 			ops->ndo_netpoll_cleanup(np->dev);
 
-		rcu_assign_pointer(np->dev->npinfo, NULL);
+		RCU_INIT_POINTER(np->dev->npinfo, NULL);
 		call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 	}
 }