configs: libretech: set SPI mode to 0

Kconfig defaults to mode 3 if CONFIG_SF_DEFAULT_MODE is not set.
It becomes an issue since meson_spifc does not support SPI_CPHA.
Needed after commit e2e95e5e25 ("spi: Update speed/mode on change").

Fixes: e2e95e5e25 ("spi: Update speed/mode on change")
Signed-off-by:Da Xue <da@libre.computer>
[narmstrong: reformated commit reference & added Fixes tag]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/configs/libretech-ac_defconfig b/configs/libretech-ac_defconfig
index ec51f2a..9abbcad 100644
--- a/configs/libretech-ac_defconfig
+++ b/configs/libretech-ac_defconfig
@@ -39,6 +39,7 @@
 CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_DM_SPI_FLASH=y
+CONFIG_SF_DEFAULT_MODE=0x0
 CONFIG_SPI_FLASH_GIGADEVICE=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_PHY_MESON_GXL=y