UBI: Silence an unintialized variable warning

My static checker complains that "val" is uninitialized when kstrtoint()
fails.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/debug.c

@@ -352,7 +352,8 @@ static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
 	} else if (dent == d->dfs_emulate_power_cut) {
 		if (kstrtoint(buf, 0, &val) != 0)
 			count = -EINVAL;
-		d->emulate_power_cut = val;
+		else
+			d->emulate_power_cut = val;
 		goto out;
 	}