CONFIG_ETRAX_SERIAL_PORT3 is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
Serial port 3 enabled
configname: CONFIG_ETRAX_SERIAL_PORT3
Linux Kernel Configuration
└─>Serial port 3 enabled
In linux kernel since version 2.6.12
Enables the ETRAX FS serial driver for ser3 (ttyS3).