thermal/drivers/broadcom: Use clamp to simplify bcm2835_thermal_temp2adc

Use clamp() to simplify bcm2835_thermal_temp2adc() and improve its
readability. Explicitly cast BIT() to int to prevent a signedness error.

Signed-off-by: Thorsten Blum <[e-mail]>
Reviewed-by: Luca Ceresoli <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

drivers/thermal/broadcom/bcm2835_thermal.c

···
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
···
 	temp -= offset;
 	temp /= slope;
 
-	if (temp < 0)
-		temp = 0;
-	if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
-		temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
-
-	return temp;
+	return clamp(temp, 0, (int)BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1);
 }
 
 static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz, int *temp)