CONFIG_GPTMR0_CLOCKSOURCE is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
Use GPTimer0 as a clocksource
configname: CONFIG_GPTMR0_CLOCKSOURCE
Blackfin Kernel Configuration
└─>Blackfin Processor Options
└─>Board customizations
└─>Use GPTimer0 as a clocksource