tipc: Fix end of loop tests for list_for_each_entry()

These tests are supposed to check if the loop exited via a break or not.
However the tests are wrong because if we did not exit via a break then
"p" is not a valid pointer.  In that case, it's the equivalent of
"if (*(u32 *)sr == *last_key) {".  That's going to work most of the time,
but there is a potential for those to be equal.

Fixes: 1593123a ("tipc: add name table dump to new netlink api")
Fixes: 1a1a143d

 ("tipc: add publication dump to new netlink api")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>