sf: Move SPI flash drivers to defconfig

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.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/BSC9132QDS_SPIFLASH_DDRCLK133_defconfig b/configs/BSC9132QDS_SPIFLASH_DDRCLK133_defconfig
index eb25a09..6e5fbaf 100644
--- a/configs/BSC9132QDS_SPIFLASH_DDRCLK133_defconfig
+++ b/configs/BSC9132QDS_SPIFLASH_DDRCLK133_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_BSC9132QDS=y
 CONFIG_SYS_EXTRA_OPTIONS="BSC9132QDS,SPIFLASH,SYS_CLK_100_DDR_133"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y