px4io: fixed the io_reg_{set,get} errors

this fixes the PX4IO state machine to avoid the io errors we were
seeing. There are still some open questions with this code, but it now
seems to give zero errors, which is an improvement!

src/modules/px4iofirmware/px4io.c

@@ -159,9 +159,6 @@ user_start(int argc, char *argv[])
 	/* start the FMU interface */
 	interface_init();
 
-	/* add a performance counter for the interface */
-	perf_counter_t interface_perf = perf_alloc(PC_ELAPSED, "interface");
-
 	/* add a performance counter for mixing */
 	perf_counter_t mixer_perf = perf_alloc(PC_ELAPSED, "mix");
 
@@ -203,11 +200,6 @@ user_start(int argc, char *argv[])
 		/* track the rate at which the loop is running */
 		perf_count(loop_perf);
 
-		/* kick the interface */
-		perf_begin(interface_perf);
-		interface_tick();
-		perf_end(interface_perf);
-
 		/* kick the mixer */
 		perf_begin(mixer_perf);
 		mixer_tick();
@@ -218,6 +210,7 @@ user_start(int argc, char *argv[])
 		controls_tick();
 		perf_end(controls_perf);
 
+#if 0
 		/* check for debug activity */
 		show_debug_messages();
 
@@ -234,6 +227,7 @@ user_start(int argc, char *argv[])
 				  (unsigned)minfo.mxordblk);
 			last_debug_time = hrt_absolute_time();
 		}
+#endif
 	}
 }