Convert CONFIG_ENV_SPI_* to Kconfig

This converts the following to Kconfig:
  CONFIG_ENV_SPI_BUS
  CONFIG_ENV_SPI_CS
  CONFIG_ENV_SPI_MAX_HZ
  CONFIG_ENV_SPI_MODE

Most of time these value are not needed, CONFIG_SF_DEFAULT
with same value is used, so I introduced CONFIG_USE_ENV_SPI_*
to force the associated value for the environment.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/configs/ls1012aqds_tfa_defconfig b/configs/ls1012aqds_tfa_defconfig
index d18d40a..99188d3 100644
--- a/configs/ls1012aqds_tfa_defconfig
+++ b/configs/ls1012aqds_tfa_defconfig
@@ -36,6 +36,12 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="fsl-ls1012a-qds"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
+CONFIG_USE_ENV_SPI_BUS=y
+CONFIG_ENV_SPI_BUS=0
+CONFIG_USE_ENV_SPI_MAX_HZ=y
+CONFIG_ENV_SPI_MAX_HZ=1000000
+CONFIG_USE_ENV_SPI_MODE=y
+CONFIG_ENV_SPI_MODE=0x03
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_DM=y
 CONFIG_SCSI_AHCI=y