CONFIG_ETRAX_SERIAL_PORT4 is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
Serial port 4 enabled
configname: CONFIG_ETRAX_SERIAL_PORT4
Linux Kernel Configuration
└─>Serial port 4 enabled
In linux kernel since version 2.6.25 (release Date: 2008-04-16)
Enables the ETRAX FS serial driver for ser4 (ttyS4).