CONFIG_OMAP_ARM_30MHZ is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_OMAP_ARM_30MHZ.
Result is shown for kernelversion 6.2.5

OMAP ARM 30 MHz CPU

configname: CONFIG_OMAP_ARM_30MHZ

Linux Kernel Configuration
└─>TI OMAP1 specific features
└─>OMAP ARM 30 MHz CPU
In linux kernel since version 2.6.12  
Enable 30MHz clock for OMAP CPU. If unsure, say N.