iio: imu: inv_icm42600: Fix alignment for DMA safety

Partial fix for this driver as a second instance was introduced in
a later patch.

____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: a095fadb ("iio: imu: inv_icm42600: add gyroscope IIO device")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-78-jic23@kernel.org

drivers/iio/imu/inv_icm42600/inv_icm42600.h

@@ -140,7 +140,7 @@ struct inv_icm42600_state {
 	struct inv_icm42600_suspended suspended;
 	struct iio_dev *indio_gyro;
 	struct iio_dev *indio_accel;
-	uint8_t buffer[2] ____cacheline_aligned;
+	uint8_t buffer[2] __aligned(IIO_DMA_MINALIGN);
 	struct inv_icm42600_fifo fifo;
 	struct {
 		int64_t gyro;