The goal of this patch is to allow compatibility with GR12/GR16/GR24 graupner receiver by :

- allowing decoding of SUMD frame with failsafe bit set
- updating stack failsafe state with the sumd failsafe info

Refer to #5817 issue

src/drivers/px4fmu/fmu.cpp

@@ -1415,6 +1415,7 @@ PX4FMU::cycle()
 			if (newBytes > 0) {
 				// parse new data
 				uint8_t sumd_rssi, rx_count;
+				bool sumd_failsafe;
 
 				rc_updated = false;
 
@@ -1422,14 +1423,14 @@ PX4FMU::cycle()
 					/* set updated flag if one complete packet was parsed */
 					sumd_rssi = RC_INPUT_RSSI_MAX;
 					rc_updated = (OK == sumd_decode(_rcs_buf[i], &sumd_rssi, &rx_count,
-									&raw_rc_count, raw_rc_values, input_rc_s::RC_INPUT_MAX_CHANNELS));
+									&raw_rc_count, raw_rc_values, input_rc_s::RC_INPUT_MAX_CHANNELS, &sumd_failsafe));
 				}
 
 				if (rc_updated) {
 					// we have a new SUMD frame. Publish it.
 					_rc_in.input_source = input_rc_s::RC_INPUT_SOURCE_PX4FMU_SUMD;
 					fill_rc_in(raw_rc_count, raw_rc_values, _cycle_timestamp,
-						   false, false, frame_drops, sumd_rssi);
+						   false, sumd_failsafe, frame_drops, sumd_rssi);
 					_rc_scan_locked = true;
 				}
 			}