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/jetson-tk1_defconfig b/configs/jetson-tk1_defconfig
index cb9c98a..8bc3015 100644
--- a/configs/jetson-tk1_defconfig
+++ b/configs/jetson-tk1_defconfig
@@ -13,6 +13,7 @@
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_NFS is not set
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SYS_NS16550=y
 CONFIG_TEGRA114_SPI=y
 CONFIG_USB=y