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/nyan-big_defconfig b/configs/nyan-big_defconfig
index f685f18..7fc1bde 100644
--- a/configs/nyan-big_defconfig
+++ b/configs/nyan-big_defconfig
@@ -19,6 +19,7 @@
 CONFIG_CROS_EC=y
 CONFIG_CROS_EC_SPI=y
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SYS_NS16550=y
 CONFIG_TEGRA114_SPI=y
 CONFIG_TPM_TIS_INFINEON=y