net: lwm2m: fix max measurement checks

Copy/paste error was checking minimum measurements where it
should have been checking maximum measurements.

Signed-off-by: Michael Scott <michael.scott@linaro.org>
diff --git a/subsys/net/lib/lwm2m/ipso_temp_sensor.c b/subsys/net/lib/lwm2m/ipso_temp_sensor.c
index b38dbc9..95fe90c 100644
--- a/subsys/net/lib/lwm2m/ipso_temp_sensor.c
+++ b/subsys/net/lib/lwm2m/ipso_temp_sensor.c
@@ -109,12 +109,12 @@
 				update_min = true;
 			}
 
-			if (sensor_value[i].val1 > min_measured_value[i].val1) {
+			if (sensor_value[i].val1 > max_measured_value[i].val1) {
 				update_max = true;
 			} else if (sensor_value[i].val1 ==
-					min_measured_value[i].val1 &&
+					max_measured_value[i].val1 &&
 				   sensor_value[i].val2 >
-					min_measured_value[i].val2) {
+					max_measured_value[i].val2) {
 				update_max = true;
 			}