The driver currently defines two different data structures to hold
Gateway Update parameters:
- legacy struct rssi_monitor_req
- unified WMI struct rssi_monitor_req
To align with the converged software architecture remove the legacy
definition and exclusively use the unified WMI definition.
Change-Id: Ia3336b68dac84ce8aeb53ea6d5be8b9f2e0f1736
CRs-Fixed: 2404088