iio: temp: maxim-thermocouple: Fix potential lack of DMA safe buffer.

[ Upstream commit f79aeb6 ]

The trick of using __aligned(IIO_DMA_MINALIGN) ensures that there is
no overlap between buffers used for DMA and those used for driver
state storage that are before the marking. It doesn't ensure
anything above state variables found after the marking. Hence
move this particular bit of state earlier in the structure.

Fixes: 10897f3 ("iio: temp: maxim_thermocouple: Fix alignment for DMA safety")
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250413103443.2420727-14-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: jic23

drivers/iio/temperature/maxim_thermocouple.c

@@ -121,9 +121,9 @@ static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
 struct maxim_thermocouple_data {
 	struct spi_device *spi;
 	const struct maxim_thermocouple_chip *chip;
+	char tc_type;
 
 	u8 buffer[16] __aligned(IIO_DMA_MINALIGN);
-	char tc_type;
 };
 
 static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,