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_SDCARD_DDRCLK100_defconfig b/configs/BSC9132QDS_SDCARD_DDRCLK100_defconfig
index 3c77f1f..4c22ce6 100644
--- a/configs/BSC9132QDS_SDCARD_DDRCLK100_defconfig
+++ b/configs/BSC9132QDS_SDCARD_DDRCLK100_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_BSC9132QDS=y
 CONFIG_SYS_EXTRA_OPTIONS="BSC9132QDS,SDCARD,SYS_CLK_100_DDR_100"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y