Convert CONFIG_SF_DEFAULT_* to Kconfig

This converts the following to Kconfig:
  CONFIG_SF_DEFAULT_BUS
  CONFIG_SF_DEFAULT_CS
  CONFIG_SF_DEFAULT_MODE
  CONFIG_SF_DEFAULT_SPEED

I use moveconfig script and then manual check on generated u-boot.cfg
to solve the remaining issue.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/configs/ls1043aqds_lpuart_defconfig b/configs/ls1043aqds_lpuart_defconfig
index ff5ea65..eb5e4da 100644
--- a/configs/ls1043aqds_lpuart_defconfig
+++ b/configs/ls1043aqds_lpuart_defconfig
@@ -40,6 +40,7 @@
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_SPI_FLASH=y
+CONFIG_SF_DEFAULT_BUS=1
 CONFIG_PHYLIB=y
 CONFIG_E1000=y
 CONFIG_PCI=y