watchdog: softdog: sort includes to avoid duplicates

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>

#include <linux/jiffies.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/reboot.h>

#include <linux/timer.h>

#include <linux/types.h>

#include <linux/watchdog.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <linux/jiffies.h>

#include <linux/kernel.h>

#define TIMER_MARGIN	60		/* Default is 60 seconds */

static unsigned int soft_margin = TIMER_MARGIN;	/* in seconds */