switch statfs to fget_light/fput_light

int fd_statfs(int fd, struct kstatfs *st)

{

	struct file *file = fget(fd);

	int fput_needed;

	struct file *file = fget_light(fd, &fput_needed);

	int error = -EBADF;

	if (file) {

		error = vfs_statfs(&file->f_path, st);

		fput(file);

		fput_light(file, fput_needed);

	}

	return error;

}