CONFIG_IRQ_REMAP is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Support for Interrupt Remapping

modulename: intel_irq_remapping.ko

configname: CONFIG_IRQ_REMAP

Linux Kernel Configuration
└─>Device Drivers
└─>IOMMU Hardware Support
└─>Support for Interrupt Remapping
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Supports Interrupt remapping for IO-APIC and MSI devices.
To use x2apic mode in the CPU's which support x2APIC enhancements or
to support platforms with CPU's having > 8 bit APIC ID, say Y.

source code:

depends
CONFIG_ACPI
CONFIG_IOMMU_SUPPORT
CONFIG_PCI_MSI
CONFIG_X86_64
CONFIG_X86_IO_APIC