spi: spi-uclass: Set slave wordlen with SPI_DEFAULT_WORDLEN

In some case wordlen may not be set. Use SPI_DEFAULT_WORDLEN as default.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
index 677c020..5561f36 100644
--- a/drivers/spi/spi-uclass.c
+++ b/drivers/spi/spi-uclass.c
@@ -158,6 +158,7 @@
 	slave->max_hz = plat->max_hz;
 	slave->mode = plat->mode;
 	slave->mode_rx = plat->mode_rx;
+	slave->wordlen = SPI_DEFAULT_WORDLEN;
 
 	return 0;
 }