sm8150-common: Force DSDS for selected device variants

This makes sure we default to ssss on TMO devices while still letting
users to setprop dsds if they wish to do so.

While this restricts disabling dsds on native dual SIM devices,
doubtfully anyone would actually want to do that.

Change-Id: I72f019c466d23a89f4c3438150b592d21b65b742