iio: dmaengine-buffer: Use sysfs_emit()

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in checks for
size and alignment.

Use sysfs_emit() for the `length_align_bytes` buffer attribute.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211216185217.1054495-3-lars@metafoo.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/buffer/industrialio-buffer-dmaengine.c

@@ -136,7 +136,7 @@ static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev,
 	struct dmaengine_buffer *dmaengine_buffer =
 		iio_buffer_to_dmaengine_buffer(buffer);
 
-	return sprintf(buf, "%zu\n", dmaengine_buffer->align);
+	return sysfs_emit(buf, "%zu\n", dmaengine_buffer->align);
 }
 
 static IIO_DEVICE_ATTR(length_align_bytes, 0444,