CONFIG_DUMMY_CONSOLE is not available for the selected architecture x86.
Result is shown for architecture alpha

CONFIG_DUMMY_CONSOLE (not configurable)

modulename: dummycon.ko

configname: CONFIG_DUMMY_CONSOLE

Linux Kernel Configuration
└─>DUMMY_CONSOLE
In linux kernel since version 2.6.20 (release Date: 2007-02-04)
source code:
drivers/video/console/dummycon.c
depends
CONFIG_VGA_HOSE