qcacld-3.0: Avoid panic in driver inactivity op timer if fw is down

It's possible that FW crashes during driver unload hence avoid panic
in driver inactivity op timer handler if fw is already down.

Change-Id: I43b520fe064ede919f5f98674d98e8861fd9a414
CRs-Fixed: 2167265

core/hdd/src/wlan_hdd_main.c

@@ -13454,6 +13454,11 @@ void hdd_drv_ops_inactivity_handler(void)
 		sizeof("shutdown")))
 		QDF_BUG(0);
 
+	if (cds_is_fw_down()) {
+		hdd_err("FW is down");
+		return;
+	}
+
 	if (cds_is_self_recovery_enabled())
 		cds_trigger_recovery(QDF_REASON_UNSPECIFIED);
 	else