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/ls1021aqds_nor_defconfig b/configs/ls1021aqds_nor_defconfig
index fb9f457..3e8b34b 100644
--- a/configs/ls1021aqds_nor_defconfig
+++ b/configs/ls1021aqds_nor_defconfig
@@ -66,6 +66,7 @@
 CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
+CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS=y
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_SYS_MAX_FLASH_BANKS=2