spi: mpc52xx: Convert to use bits_per_word_mask

This controller only supports 8-bit word length.
Set bits_per_word_mask so spi core will reject transfers that attempt to use
an unsupported bits_per_word value.
Also remove the duplicate code to test spi->mode, it is done by spi core.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-mpc52xx.c

@@ -357,17 +357,6 @@ static void mpc52xx_spi_wq(struct work_struct *work)
  * spi_master ops
  */
 
-static int mpc52xx_spi_setup(struct spi_device *spi)
-{
-	if (spi->bits_per_word % 8)
-		return -EINVAL;
-
-	if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST))
-		return -EINVAL;
-
-	return 0;
-}
-
 static int mpc52xx_spi_transfer(struct spi_device *spi, struct spi_message *m)
 {
 	struct mpc52xx_spi *ms = spi_master_get_devdata(spi->master);
@@ -430,9 +419,9 @@ static int mpc52xx_spi_probe(struct platform_device *op)
 		goto err_alloc;
 	}
 
-	master->setup = mpc52xx_spi_setup;
 	master->transfer = mpc52xx_spi_transfer;
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
+	master->bits_per_word_mask = SPI_BPW_MASK(8);
 	master->dev.of_node = op->dev.of_node;
 
 	platform_set_drvdata(op, master);