powerpc/km: drop unused CONFIG_SYS_DTT_LOW_TEMP

This define is not used in u-boot code, we can drop this define safely.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
diff --git a/include/configs/km/km83xx-common.h b/include/configs/km/km83xx-common.h
index 0ff866a..5e075c8 100644
--- a/include/configs/km/km83xx-common.h
+++ b/include/configs/km/km83xx-common.h
@@ -223,7 +223,6 @@
 #define CONFIG_DTT_LM75		/* ON Semi's LM75 */
 #define CONFIG_DTT_SENSORS	{0, 1, 2, 3}	/* Sensor addresses */
 #define CONFIG_SYS_DTT_MAX_TEMP	70
-#define CONFIG_SYS_DTT_LOW_TEMP	-30
 #define CONFIG_SYS_DTT_HYSTERESIS	3
 #define CONFIG_SYS_DTT_BUS_NUM		1
 
diff --git a/include/configs/km82xx.h b/include/configs/km82xx.h
index b23cb96..726c646b 100644
--- a/include/configs/km82xx.h
+++ b/include/configs/km82xx.h
@@ -271,7 +271,6 @@
 #define CONFIG_DTT_LM75			/* ON Semi's LM75		*/
 #define CONFIG_DTT_SENSORS	{0}	/* Sensor addresses		*/
 #define CONFIG_SYS_DTT_MAX_TEMP	70
-#define CONFIG_SYS_DTT_LOW_TEMP	-30
 #define CONFIG_SYS_DTT_HYSTERESIS	3
 #define CONFIG_SYS_DTT_BUS_NUM		2