thermal/drivers/stm32: Use predefined HZ_PER_MHZ instead of a custom one

Use predefined HZ_PER_MHZ instead of a custom one. No functional changes.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260114092808.273695-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Author: andy-shev

drivers/thermal/st/stm_thermal.c

@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/thermal.h>
+#include <linux/units.h>
 
 #include "../thermal_hwmon.h"
 
@@ -76,7 +77,6 @@
 
 /* Constants */
 #define ADJUST			100
-#define ONE_MHZ			1000000
 #define POLL_TIMEOUT		5000
 #define STARTUP_TIME		40
 #define TS1_T0_VAL0		30000  /* 30 celsius */
@@ -205,7 +205,7 @@ static int stm_thermal_calibration(struct stm_thermal_sensor *sensor)
 		return -EINVAL;
 
 	prescaler = 0;
-	clk_freq /= ONE_MHZ;
+	clk_freq /= HZ_PER_MHZ;
 	if (clk_freq) {
 		while (prescaler <= clk_freq)
 			prescaler++;