selftests: rds: config: disable modules

The run.sh script explicitly checks that CONFIG_MODULES is disabled.

By default, this config option is enabled. Explicitly disable it to be
able to run the RDS tests.

Note that writing '# CONFIG_(...) is not set' is usually recommended to
disable an option in the .config, but it looks like selftests usually
set 'CONFIG_(...)=n', which looks clearer.

Fixes: 0f5d6800 ("selftests: rds: add tools/testing/selftests/net/rds/config")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Allison Henderson <achender@kernel.org>
Link: https://patch.msgid.link/20260520-net-rds-config-modules-v1-1-2100df02fe9a@kernel.org


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