default or selected kernelversion does not have config value CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK.
Result is shown for kernelversion 6.9.9

Clocksource PRCMU Timer sched_clock

configname: CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK

Linux Kernel Configuration
└─>Device Drivers
└─>Clock Source drivers
└─>Clocksource PRCMU Timer sched_clock
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Use the always on PRCMU Timer as sched_clock