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

Periodic Interval Timer (PIT) support

configname: CONFIG_ATMEL_CLOCKSOURCE_PIT

Linux Kernel Configuration
└─>AT91/Microchip SoCs
└─>Periodic Interval Timer (PIT) support
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Select this to get a clocksource based on the Atmel Periodic Interval
Timer. It has a relatively low resolution and the TC Block clocksource
should be preferred.