Convert CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS to Kconfig

This converts the following to Kconfig:
   CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/blanche_defconfig b/configs/blanche_defconfig
index 1e117c9..82d54de 100644
--- a/configs/blanche_defconfig
+++ b/configs/blanche_defconfig
@@ -53,6 +53,7 @@
 CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
+CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS=y
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_SPANSION=y