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/chromebook_link_defconfig b/configs/chromebook_link_defconfig
index d03a782..ac64877 100644
--- a/configs/chromebook_link_defconfig
+++ b/configs/chromebook_link_defconfig
@@ -21,6 +21,9 @@
 CONFIG_CROS_EC=y
 CONFIG_CROS_EC_LPC=y
 CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_GIGADEVICE=y
+CONFIG_SPI_FLASH_MACRONIX=y
+CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_PCI=y
 CONFIG_DM_RTC=y
 CONFIG_DEBUG_UART=y