iio: magnetometer: rm3100-spi: remove bits_per_word = 8

Remove setting bits_per_word = 8 from the rm3100 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-v1-11-341f85fcfe11@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: dlech

drivers/iio/magnetometer/rm3100-spi.c

@@ -32,7 +32,6 @@ static int rm3100_probe(struct spi_device *spi)
 	spi->mode = SPI_MODE_0;
 	/* Data rates cannot exceed 1Mbits. */
 	spi->max_speed_hz = 1000000;
-	spi->bits_per_word = 8;
 	ret = spi_setup(spi);
 	if (ret)
 		return ret;