[VAMOS] osmo-bts-omldummy: allocate shadow timeslots
[VAMOS] osmo-bts-omldummy: allocate shadow timeslots

Change-Id: I4aa9a8bb35bd828d6f25d5690297e727dace5974
Related: SYS#4895, OS#4941, SYS#5316, OS#4940

osmocom/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts