[source] ar71xx: fix RB4xx SPI driver mode bits

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/c3a8b87773b7045f20ec288ecf55b3d5af5000ba

commit c3a8b87773b7045f20ec288ecf55b3d5af5000ba
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Wed Jan 11 12:26:27 2017 +0100

    ar71xx: fix RB4xx SPI driver mode bits
    
    Accept SPI_TX_DUAL in device mode to fix the CPLD driver
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 target/linux/ar71xx/files/drivers/spi/spi-rb4xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/linux/ar71xx/files/drivers/spi/spi-rb4xx.c b/target/linux/ar71xx/files/drivers/spi/spi-rb4xx.c
index d8c71fb..9175fc7 100644
--- a/target/linux/ar71xx/files/drivers/spi/spi-rb4xx.c
+++ b/target/linux/ar71xx/files/drivers/spi/spi-rb4xx.c
@@ -261,7 +261,7 @@ static int rb4xx_spi_setup(struct spi_device *spi)
 	struct rb4xx_spi *rbspi = spi_master_get_devdata(spi->master);
 	unsigned long flags;
 
-	if (spi->mode & ~(SPI_CS_HIGH)) {
+	if (spi->mode & ~(SPI_CS_HIGH | SPI_TX_DUAL)) {
 		dev_err(&spi->dev, "mode %x not supported\n",
 			(unsigned) spi->mode);
 		return -EINVAL;