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

Software Shutdown Support


Linux Kernel Configuration
└─>CRIS v10 options
└─>Software Shutdown Support
In linux kernel since version 2.6.12  
Enable this if ETRAX is used with a power-supply that can be turned
off and on with PS_ON signal. Gives the possibility to detect
powerbutton and then do a power off after unmounting disks.