spi: spi-mxs: Remove unused bits_per_word variable

The bits_per_word variable is not used after commit 24778be2
"spi: convert drivers to use bits_per_word_mask".
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-mxs.c

@@ -67,13 +67,8 @@ static int mxs_spi_setup_transfer(struct spi_device *dev,
 {
 	struct mxs_spi *spi = spi_master_get_devdata(dev->master);
 	struct mxs_ssp *ssp = &spi->ssp;
-	uint8_t bits_per_word;
 	uint32_t hz = 0;
 
-	bits_per_word = dev->bits_per_word;
-	if (t && t->bits_per_word)
-		bits_per_word = t->bits_per_word;
-
 	hz = dev->max_speed_hz;
 	if (t && t->speed_hz)
 		hz = min(hz, t->speed_hz);