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/C29XPCIE_NOR_SECBOOT_defconfig b/configs/C29XPCIE_NOR_SECBOOT_defconfig
index 8d46871..110e597 100644
--- a/configs/C29XPCIE_NOR_SECBOOT_defconfig
+++ b/configs/C29XPCIE_NOR_SECBOOT_defconfig
@@ -3,6 +3,8 @@
 CONFIG_TARGET_C29XPCIE=y
 CONFIG_SYS_EXTRA_OPTIONS="C29XPCIE,36BIT,SECURE_BOOT"
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_EON=y
+CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y