There are already Kconfig options for SPI flash drivers, but we
have not moved them from config.h to defconfig files. This commit
does this in a batch.
CONFIG_ARM=y
CONFIG_TARGET_BG0900=y
CONFIG_SPL=y
# CONFIG_CMD_IMLS is not set
# CONFIG_CMD_FLASH is not set
CONFIG_CMD_GPIO=y
CONFIG_SPI_FLASH=y
CONFIG_SPI_FLASH_BAR=y
CONFIG_SPI_FLASH_STMICRO=y
