CONFIG_METAG is not available for thedefaultarchitecture x86.
Result is shown for architecture metag

CONFIG_METAG (not configurable)

modulename: irq-metag-ext.ko

configname: CONFIG_METAG

Linux Kernel Configuration
└─>METAG
In linux kernel since version 3.1 (release Date: 2011-10-24)  
source code:
drivers/irqchip/irq-metag-ext.c

is selected by
CONFIG_IR_IMG