As a boot up flow of AWR12xx (at rlDevicePowerOn function call), it raises HostIRQ line to Host to notify about pending SPI Asychronous message (bootup async event from AWR12xx to TDA2x [Host]). At this event, radar-SDK application should get interrupted and call Bsp_ar12xxAsyncEvtHandlerCb. In TDA2x this callback function is stiched to one of GPIO (connected with HostIRQ of AWR12xx), which will get invoked as HostIRQ is up.
