CONFIG_MACH_OMAP3_BEAGLE is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

OMAP3 BEAGLE board

modulename: board-omap3beagle.ko

configname: CONFIG_MACH_OMAP3_BEAGLE

Linux Kernel Configuration
└─>TI OMAP/AM/DM/DRA Family
└─>TI OMAP2/3/4 Specific Features
└─>OMAP3 BEAGLE board
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  
source code:
arch/arm/mach-omap2/board-omap3beagle.c