iio: dac: ad5761: remove bits_per_word = 8

Remove setting bits_per_word = 8 from the ad5761 driver. This is the
default value for SPI transfers, so it is not necessary to explicitly
set it.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250505-iio-remove-bits_per_word-8-v1-4-341f85fcfe11@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/ad5761.c

@@ -137,13 +137,11 @@ static int _ad5761_spi_read(struct ad5761_state *st, u8 addr, u16 *val)
 	struct spi_transfer xfers[] = {
 		{
 			.tx_buf = &st->data[0].d8[1],
-			.bits_per_word = 8,
 			.len = 3,
 			.cs_change = true,
 		}, {
 			.tx_buf = &st->data[1].d8[1],
 			.rx_buf = &st->data[2].d8[1],
-			.bits_per_word = 8,
 			.len = 3,
 		},
 	};