px4io: input_rc only publish new successful decodes

- previously an invalid decode would continue to be transferred to the FMU (at 50 Hz) and published to the rest of the system as successfully decoded new RC data
 - by only publishing new successful decodes we can more effectively discard invalid data in downstream consumers

src/modules/px4iofirmware/controls.c

@@ -369,6 +369,8 @@ controls_tick()
 		} else {
 			r_raw_rc_flags &= ~(PX4IO_P_RAW_RC_FLAGS_MAPPING_OK);
 		}
+
+		r_page_raw_rc_input[PX4IO_P_RAW_FRAME_COUNT]++;
 	}
 
 	/*