spi: spi-gpio.c tests SPI_MASTER_NO_RX bit twice, but not SPI_MASTER_NO_TX

The SPI_MASTER_NO_TX bit (can't do buffer write) wasn't tested.  This
code was introduced in commit 3c8e1a84 (spi/spi-gpio: add support for
controllers without MISO or MOSI pin).  This patch fixes a bug in
choosing which transfer ops to use.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/spi_gpio.c b/drivers/spi/spi_gpio.c
index e24a634..63e51b0 100644
--- a/drivers/spi/spi_gpio.c
+++ b/drivers/spi/spi_gpio.c
@@ -350,7 +350,7 @@
 	spi_gpio->bitbang.master = spi_master_get(master);
 	spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
 
-	if ((master_flags & (SPI_MASTER_NO_RX | SPI_MASTER_NO_RX)) == 0) {
+	if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) {
 		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
 		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
 		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;