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/ae350_rv64_xip_defconfig b/configs/ae350_rv64_xip_defconfig
index b5bdf94..49511ab 100644
--- a/configs/ae350_rv64_xip_defconfig
+++ b/configs/ae350_rv64_xip_defconfig
@@ -31,6 +31,7 @@
 CONFIG_FTSDC010_SDIO=y
 CONFIG_DM_MTD=y
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_SYS_FLASH_CFI_WIDTH_16BIT=y
 CONFIG_CFI_FLASH=y
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_CFI=y