spi/bfin_spi: reject unsupported SPI modes

Who knows what people will try!
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

drivers/spi/spi_bfin5xx.c

@@ -1022,6 +1022,10 @@ static int bfin_spi_setup(struct spi_device *spi)
 	}
 
 	/* translate common spi framework into our register */
+	if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) {
+		dev_err(&spi->dev, "unsupported spi modes detected\n");
+		goto error;
+	}
 	if (spi->mode & SPI_CPOL)
 		chip->ctl_reg |= BIT_CTL_CPOL;
 	if (spi->mode & SPI_CPHA)