kernel/reboot: replace sprintf() with sysfs_emit()

As Documentation/filesystems/sysfs.rst suggested, show() should only use
sysfs_emit() or sysfs_emit_at() when formatting the value to be returned
to user space.

No functional change intended.

Link: https://lkml.kernel.org/r/20241105094941.33739-1-zhangguopeng@kylinos.cn
Signed-off-by: zhangguopeng <zhangguopeng@kylinos.cn>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Fabio Estevam <festevam@denx.de>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: zhangguopeng

kernel/reboot.c

@@ -1137,7 +1137,7 @@ static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char
 		val = REBOOT_UNDEFINED_STR;
 	}
 
-	return sprintf(buf, "%s\n", val);
+	return sysfs_emit(buf, "%s\n", val);
 }
 static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
 			  const char *buf, size_t count)
@@ -1167,7 +1167,7 @@ static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
 #ifdef CONFIG_X86
 static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%d\n", reboot_force);
+	return sysfs_emit(buf, "%d\n", reboot_force);
 }
 static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
 			  const char *buf, size_t count)
@@ -1214,7 +1214,7 @@ static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char
 		val = REBOOT_UNDEFINED_STR;
 	}
 
-	return sprintf(buf, "%s\n", val);
+	return sysfs_emit(buf, "%s\n", val);
 }
 static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
 			  const char *buf, size_t count)
@@ -1247,7 +1247,7 @@ static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
 #ifdef CONFIG_SMP
 static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%d\n", reboot_cpu);
+	return sysfs_emit(buf, "%d\n", reboot_cpu);
 }
 static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
 			  const char *buf, size_t count)