bugfix for some negative temperature conversions

mission/devices/max1227.cpp

@@ -25,4 +25,7 @@ void max1227::prepareExternallyClockedTemperatureRead(uint8_t *spiBuf, size_t &s
   sz += 25;
 }
 
-float max1227::getTemperature(int16_t temp) { return static_cast<float>(temp) * 0.125; }
+float max1227::getTemperature(uint16_t raw) {
+	float temp = static_cast<float>((-2048 * (raw >> 11)) + (raw & 0x7FF)) * 0.125;
+	return temp;
+}