ipc: add missing override

Change-Id: Ib1493ac10b40d24372075d4cebd67015192675e0
diff --git a/Transceiver52M/device/ipc/IPCDevice.h b/Transceiver52M/device/ipc/IPCDevice.h
index 35279a2..f70c95e 100644
--- a/Transceiver52M/device/ipc/IPCDevice.h
+++ b/Transceiver52M/device/ipc/IPCDevice.h
@@ -199,7 +199,7 @@
 	virtual double minRxGain(void) override;
 
 	/* FIXME: return rx_gains[chan] ? receive factor from IPC Driver? */
-	double rssiOffset(size_t chan) { return 0.0f; };
+	double rssiOffset(size_t chan) override { return 0.0f; };
 
 	double setPowerAttenuation(int atten, size_t chan) override;
 	double getPowerAttenuation(size_t chan = 0) override;