CONFIG_OMAP_ARM_150MHZ is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_OMAP_ARM_150MHZ.
Result is shown for kernelversion 6.2.5

OMAP ARM 150 MHz CPU

configname: CONFIG_OMAP_ARM_150MHZ

Linux Kernel Configuration
└─>TI OMAP1 specific features
└─>OMAP ARM 150 MHz CPU
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
Enable 150MHz clock for OMAP CPU. If unsure, say N.