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

CONFIG_MACH_OMAP_GENERIC (not configurable)

modulename: board-generic.ko

configname: CONFIG_MACH_OMAP_GENERIC

Linux Kernel Configuration
└─>TI OMAP/AM/DM/DRA Family
└─>TI OMAP2/3/4 Specific Features
└─>MACH_OMAP_GENERIC
In linux kernel since version 2.6.12  
source code: