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/blanche_defconfig b/configs/blanche_defconfig
index 01e9ea3..f4bb406 100644
--- a/configs/blanche_defconfig
+++ b/configs/blanche_defconfig
@@ -55,6 +55,7 @@
 CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y
+CONFIG_SYS_FLASH_CFI_WIDTH_16BIT=y
 CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS=y
 CONFIG_SYS_FLASH_CFI=y
 CONFIG_DM_SPI_FLASH=y