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/T2080RDB_SDCARD_defconfig b/configs/T2080RDB_SDCARD_defconfig
index 55a5c5a..fc61d1a 100644
--- a/configs/T2080RDB_SDCARD_defconfig
+++ b/configs/T2080RDB_SDCARD_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="PPC_T2080,RAMBOOT_PBL,SPL_FSL_PBL,SDCARD"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y