CONFIG_ETRAX_FLASH_BUSWIDTH is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_FLASH_BUSWIDTH.
Result is shown for kernelversion 6.7-rc3

Buswidth of NOR flash in bytes

configname: CONFIG_ETRAX_FLASH_BUSWIDTH

Linux Kernel Configuration
└─>Hardware setup
└─>Buswidth of NOR flash in bytes
In linux kernel since version 2.6.12  
Width in bytes of the NOR Flash bus (1, 2 or 4). Is usually 2.