spi: Eliminate 3WIRE spi_transfer check

Checking for SPI_3WIRE isn't needed.  spi_setup() already prevents 3WIRE
mode from being combined with DUAL or QUAD mode support.  So there is no
need to differentiate between a single bit device with SPI_3WIRE set and
one with without.  It doesn't change the allowed bit widths.
Signed-off-by: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi.c

@@ -1678,9 +1678,6 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
 				!(spi->mode & SPI_TX_QUAD))
 				return -EINVAL;
-			if ((spi->mode & SPI_3WIRE) &&
-				(xfer->tx_nbits != SPI_NBITS_SINGLE))
-				return -EINVAL;
 		}
 		/* check transfer rx_nbits */
 		if (xfer->rx_buf) {
@@ -1694,9 +1691,6 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
 				!(spi->mode & SPI_RX_QUAD))
 				return -EINVAL;
-			if ((spi->mode & SPI_3WIRE) &&
-				(xfer->rx_nbits != SPI_NBITS_SINGLE))
-				return -EINVAL;
 		}
 	}