CONFIG_IA64_ESI is not available for thedefaultarchitecture x86.
Result is shown for architecture ia64

ESI (Extensible SAL Interface) support

modulename: esi.ko

configname: CONFIG_IA64_ESI

Linux Kernel Configuration
└─>Processor type and features
└─>ESI (Extensible SAL Interface) support
In linux kernel since version 2.6.19 (release Date: 2006-11-29)  
If you say Y here, support is built into the kernel to
make ESI calls. ESI calls are used to support vendor-specific
firmware extensions, such as the ability to inject memory-errors
for test-purposes. If you're unsure, say N.

source code: