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/T1042D4RDB_SPIFLASH_defconfig b/configs/T1042D4RDB_SPIFLASH_defconfig
index 556719e..307de29 100644
--- a/configs/T1042D4RDB_SPIFLASH_defconfig
+++ b/configs/T1042D4RDB_SPIFLASH_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="PPC_T1042,T1042D4RDB,RAMBOOT_PBL,SPL_FSL_PBL,SPIFLASH,T104XD4RDB,SYS_FSL_DDR4"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y