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_rv32_xip_defconfig b/configs/ae350_rv32_xip_defconfig
index 62fb51b..16ff634 100644
--- a/configs/ae350_rv32_xip_defconfig
+++ b/configs/ae350_rv32_xip_defconfig
@@ -30,6 +30,7 @@
 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