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

CONFIG_XSCALE_PMU (not configurable)

configname: CONFIG_XSCALE_PMU

Linux Kernel Configuration
└─>System Type
└─>XSCALE_PMU
In linux kernel since version 2.6.12  
depends
CONFIG_CPU_XSCALE
NOT CONFIG_XSCALE_PMU_TIMER