spi: Remove duplicate code to set default bits_per_word setting

The implementation in spi_setup() already set spi->bits_per_word = 8 when
spi->bits_per_word is 0 before calling spi->master->setup.
So we don't need to do it again in setup() callback.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-fsl-dspi.c

@@ -373,9 +373,6 @@ static int dspi_setup(struct spi_device *spi)
 	if (!spi->max_speed_hz)
 		return -EINVAL;
 
-	if (!spi->bits_per_word)
-		spi->bits_per_word = 8;
-
 	return dspi_setup_transfer(spi, NULL);
 }