tipc: fix bug in function tipc_nl_node_dump_monitor

tipc: fix bug in function tipc_nl_node_dump_monitor

Commit f4740415d9e3 ("tipc: fix infinite loop when dumping link monitor
summary") intended to fix a problem with user tool looping when max
number of bearers are enabled.

Unfortunately, the wrong version of the commit was posted, so the
problem was not solved at all.

This commit adds the missing part.

Fixes: f4740415d9e3 ("tipc: fix infinite loop when dumping link monitor summary")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>