CONFIG_ARCH_OMAP2PLUS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

TI OMAP2/3/4

configname: CONFIG_ARCH_OMAP2PLUS

OMAP System Type
└─>TI OMAP2/3/4
In linux kernel since version 2.6.34 (release Date: 2010-05-16)  
"Systems based on OMAP2, OMAP3 or OMAP4"


is selected by
CONFIG_MACH_OMAP_4430SDP