thermal/core: Use clamp() helper in the stepwise governor

The code is actually clampling the next cooling device state using the
lowest and highest states of the thermal instance.

That code can be replaced by the clamp() macro which does exactly the
same. It results in a simpler routine to read.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220629151012.3115773-1-daniel.lezcano@linaro.orgSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/thermal/gov_step_wise.c

@@ -11,6 +11,7 @@
  */
 
 #include <linux/thermal.h>
+#include <linux/minmax.h>
 #include <trace/events/thermal.h>
 
 #include "thermal_core.h"
@@ -52,10 +53,7 @@ static unsigned long get_target_state(struct thermal_instance *instance,
 
 	if (!instance->initialized) {
 		if (throttle) {
-			next_target = (cur_state + 1) >= instance->upper ?
-					instance->upper :
-					((cur_state + 1) < instance->lower ?
-					instance->lower : (cur_state + 1));
+			next_target = clamp((cur_state + 1), instance->lower, instance->upper);
 		} else {
 			next_target = THERMAL_NO_TARGET;
 		}
@@ -66,10 +64,7 @@ static unsigned long get_target_state(struct thermal_instance *instance,
 	switch (trend) {
 	case THERMAL_TREND_RAISING:
 		if (throttle) {
-			next_target = cur_state < instance->upper ?
-				    (cur_state + 1) : instance->upper;
-			if (next_target < instance->lower)
-				next_target = instance->lower;
+			next_target = clamp((cur_state + 1), instance->lower, instance->upper);
 		}
 		break;
 	case THERMAL_TREND_RAISE_FULL:
@@ -82,9 +77,7 @@ static unsigned long get_target_state(struct thermal_instance *instance,
 				next_target = THERMAL_NO_TARGET;
 		} else {
 			if (!throttle) {
-				next_target = cur_state - 1;
-				if (next_target > instance->upper)
-					next_target = instance->upper;
+				next_target = clamp((cur_state - 1), instance->lower, instance->upper);
 			}
 		}
 		break;