default or selected kernelversion does not have config value CONFIG_MTD_FORTUNET.
Result is shown for kernelversion 6.2.5

CFI Flash device mapped on the FortuNet board

modulename: fortunet.ko

configname: CONFIG_MTD_FORTUNET

Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Mapping drivers for chip access
└─>CFI Flash device mapped on the FortuNet board
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This enables access to the Flash on the FortuNet board. If you
have such a board, say 'Y'.

source code:
depends
CONFIG_MTD
CONFIG_MTD_CFI
CONFIG_SA1100_FORTUNET