Convert CONFIG_SYS_FLASH_CFI_WIDTH to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_FLASH_CFI_WIDTH

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/rcar3_salvator-x_defconfig b/configs/rcar3_salvator-x_defconfig
index 7bcbb3a..7263b32 100644
--- a/configs/rcar3_salvator-x_defconfig
+++ b/configs/rcar3_salvator-x_defconfig
@@ -75,6 +75,7 @@
 CONFIG_MTD=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_SYS_FLASH_CFI_WIDTH_16BIT=y
 CONFIG_CFI_FLASH=y
 CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS=y
 CONFIG_FLASH_CFI_MTD=y