CONFIG_ACPI_SRAT is not available for thedefaultarchitecture x86.
Result is shown for architecture i386

CONFIG_ACPI_SRAT (not configurable)

modulename: srat.ko

configname: CONFIG_ACPI_SRAT

Linux Kernel Configuration
└─>Processor type and features
└─>ACPI_SRAT
In linux kernel since version 2.6.12  
source code:
selects
CONFIG_ACPI_NUMA