CONFIG_SPARSE_IRQ is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Support sparse irq numbering

configname: CONFIG_SPARSE_IRQ

Linux Kernel Configuration
└─>Kernel options
└─>Support sparse irq numbering
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
This enables support for sparse irqs. This is useful for distro
kernels that want to define a high CONFIG_NR_CPUS value but still
want to have low kernel memory footprint on smaller machines.

( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
out the irq_desc[] array in a more NUMA-friendly way. )

If you don't know what to do here, say N.