CONFIG_MACH_OMAP_GENERIC is not available for the selected architecture x86.
Result is shown for architecture arm

Generic OMAP2+ board

modulename: board-generic.ko

configname: CONFIG_MACH_OMAP_GENERIC

Linux Kernel Configuration
└─>TI OMAP2/3/4 Specific Features
└─>Generic OMAP2+ board
In linux kernel since version 2.6.12 )
Support for generic TI OMAP2+ boards using Flattened Device Tree.
More information at <a href="https://www.kernel.org/doc/Documentation/devicetree
">Documentation/devicetree
</a>
source code:
arch/arm/mach-omap2/board-generic.c
depends
CONFIG_ARCH_OMAP2PLUS or CONFIG_ARCH_OMAP1 |
| CONFIG_ARCH_OMAP15XX or CONFIG_ARCH_OMAP16XX

is depended by
CONFIG_SOC_AM43XX