netconsole: do not release spin_lock when calling __netpoll_cleanup

With the previous patch applied, __netpoll_cleanup() is non-block now,
so we don't need to release the spin_lock before calling it.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/netconsole.c

@@ -640,12 +640,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
 				 * rtnl_lock already held
 				 */
 				if (nt->np.dev) {
-					spin_unlock_irqrestore(
-							      &target_list_lock,
-							      flags);
 					__netpoll_cleanup(&nt->np);
-					spin_lock_irqsave(&target_list_lock,
-							  flags);
 					dev_put(nt->np.dev);
 					nt->np.dev = NULL;
 					netconsole_target_put(nt);