iio: adc: ad7380: disable offload before using SPI bus

Move disabling of the SPI offload before attempting to use the SPI bus
to write a register in ad7380_offload_buffer_predisable().

This caused a crash in the spi_engine_irq() interrupt handler due to
being in an invalid state.

Fixes: bbeaec8 ("iio: ad7380: add support for SPI offload")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Angelo Dureghello <adureghello@baylibre.com>
Link: https://patch.msgid.link/20250320-iio-adc-ad7380-fix-spi-offload-buffer-predisable-v1-1-6912ac8c0ae0@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7380.c

@@ -1211,6 +1211,9 @@ static int ad7380_offload_buffer_predisable(struct iio_dev *indio_dev)
 	struct ad7380_state *st = iio_priv(indio_dev);
 	int ret;
 
+	spi_offload_trigger_disable(st->offload, st->offload_trigger);
+	spi_unoptimize_message(&st->offload_msg);
+
 	if (st->seq) {
 		ret = regmap_update_bits(st->regmap,
 					 AD7380_REG_ADDR_CONFIG1,
@@ -1222,10 +1225,6 @@ static int ad7380_offload_buffer_predisable(struct iio_dev *indio_dev)
 		st->seq = false;
 	}
 
-	spi_offload_trigger_disable(st->offload, st->offload_trigger);
-
-	spi_unoptimize_message(&st->offload_msg);
-
 	return 0;
 }