iio: dac: ad7293: Fix alignment for DMA safety

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_DMA_MINALIGN definition.

Fixes: 0bb12606c0 ("iio:dac:ad7293: add support for AD7293")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Antoniu Miclaus <antoniu.miclaus@analog.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-57-jic23@kernel.org

drivers/iio/dac/ad7293.c

@@ -144,7 +144,7 @@ struct ad7293_state {
 	struct regulator *reg_avdd;
 	struct regulator *reg_vdrive;
 	u8 page_select;
-	u8 data[3] ____cacheline_aligned;
+	u8 data[3] __aligned(IIO_DMA_MINALIGN);
 };
 
 static int ad7293_page_select(struct ad7293_state *st, unsigned int reg)