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/P1010RDB-PB_36BIT_NOR_SECBOOT_defconfig b/configs/P1010RDB-PB_36BIT_NOR_SECBOOT_defconfig
index e71e0c6..982f829 100644
--- a/configs/P1010RDB-PB_36BIT_NOR_SECBOOT_defconfig
+++ b/configs/P1010RDB-PB_36BIT_NOR_SECBOOT_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_P1010RDB=y
 CONFIG_SYS_EXTRA_OPTIONS="P1010RDB_PB,36BIT,SECURE_BOOT"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y