AP_IOMCU: run main loop at max rate

removed delay in main loop to reduce latency of RC input. This works
as we only have one thread

libraries/AP_IOMCU/iofirmware/iofirmware.cpp

@@ -178,7 +178,9 @@ void AP_IOMCU_FW::init()
 
 void AP_IOMCU_FW::update()
 {
-    eventmask_t mask = chEvtWaitAnyTimeout(~0, chTimeMS2I(1));
+    // we are not running any other threads, so we can use an
+    // immediate timeout here for lowest latency
+    eventmask_t mask = chEvtWaitAnyTimeout(~0, TIME_IMMEDIATE);
 
     // we get the timestamp once here, and avoid fetching it
     // within the DMA callbacks