ipmi/watchdog: add missing newlines when printing parameters by sysfs

When I cat some ipmi_watchdog parameters by sysfs, it displays as
follows. It's better to add a newline for easy reading.

root@(none):/# cat /sys/module/ipmi_watchdog/parameters/action
resetroot@(none):/# cat /sys/module/ipmi_watchdog/parameters/preaction
pre_noneroot@(none):/# cat /sys/module/ipmi_watchdog/parameters/preop
preop_noneroot@(none):/#
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Message-Id: <1595313309-43881-1-git-send-email-wangxiongfeng2@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_watchdog.c

@@ -232,12 +232,17 @@ static int set_param_str(const char *val, const struct kernel_param *kp)
 static int get_param_str(char *buffer, const struct kernel_param *kp)
 {
 	action_fn fn = (action_fn) kp->arg;
-	int       rv;
+	int rv, len;
 
 	rv = fn(NULL, buffer);
 	if (rv)
 		return rv;
-	return strlen(buffer);
+
+	len = strlen(buffer);
+	buffer[len++] = '\n';
+	buffer[len] = 0;
+
+	return len;
 }