allscenarios-linux.conf: Disable networkd

We have merged in the inclusion of NetworkManager in the reference
images so we can disable networkd to avoid runtime conflict.

Fixes https://git.ostc-eu.org/OSTC/OHOS/meta-ohos/-/issues/112



Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>