CONFIG_MACH_OSIRIS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Simtec IM2440D20 (OSIRIS) module

configname: CONFIG_MACH_OSIRIS

Linux Kernel Configuration
└─>Samsung S3C24XX SoCs Support
└─>Simtec IM2440D20 (OSIRIS) module
In linux kernel since version 2.6.17 (release Date: 2006-06-17)  
Say Y here if you are using the Simtec IM2440D20 module, also
known as the Osiris.