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_BLACKFIN=y
CONFIG_TARGET_BF537_PNAV=y
CONFIG_CMD_GPIO=y
# CONFIG_CMD_SETEXPR is not set
CONFIG_NET_RANDOM_ETHADDR=y
CONFIG_SPI_FLASH=y
CONFIG_SPI_FLASH_STMICRO=y
