samples/susbys/mgmt/mcumgr/smp_svr: add nrf5 configs

Added default configuration files for nrf5 boards so the sample
is building with expected features for these boards.

Would be greater to use OVERLAY_CONFIG instead of files addition,
but that doesn't work from CMakeLists.txt scope.

fixes #24442

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
4 files changed