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/am335x_boneblack_vboot_defconfig b/configs/am335x_boneblack_vboot_defconfig
index 283489c..ad40b07 100644
--- a/configs/am335x_boneblack_vboot_defconfig
+++ b/configs/am335x_boneblack_vboot_defconfig
@@ -15,5 +15,6 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DM_MMC=y
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_ETH=y
 CONFIG_SYS_NS16550=y