mavlink battery_status: report actual cell voltages

src/modules/mavlink/mavlink_messages.cpp

@@ -737,10 +737,12 @@ protected:
 				}
 
 				static constexpr int mavlink_cells_max = (sizeof(bat_msg.voltages) / sizeof(bat_msg.voltages[0]));
+				static constexpr int uorb_cells_max =
+					(sizeof(battery_status.voltage_cell_v) / sizeof(battery_status.voltage_cell_v[0]));
 
 				for (int cell = 0; cell < mavlink_cells_max; cell++) {
-					if ((battery_status.cell_count > 0) && (cell < battery_status.cell_count) && battery_status.connected) {
-						bat_msg.voltages[cell] = (battery_status.voltage_v / battery_status.cell_count) * 1000.0f;
+					if (battery_status.connected && (cell < battery_status.cell_count) && (cell < uorb_cells_max)) {
+						bat_msg.voltages[cell] = battery_status.voltage_cell_v[cell] * 1000.0f;
 
 					} else {
 						bat_msg.voltages[cell] = UINT16_MAX;