net: netconsole: selftests: Change the IP subnet

Use a less populated IP range to run the tests, as suggested by Petr in
Link: https://lore.kernel.org/netdev/87ikvukv3s.fsf@nvidia.com/

.

Suggested-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20241029090030.1793551-2-leitao@debian.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>