CONFIG_DTCM_NR_PAGES is not available for thedefaultarchitecture x86.
Result is shown for architecture csky

Page count of DTCM size: NR*4KB

configname: CONFIG_DTCM_NR_PAGES

Linux Kernel Configuration
└─>Processor type and features
└─>Tightly-Coupled/Sram Memory
└─>Page count of DTCM size: NR*4KB
In linux kernel since version 5.1 (release Date: 2019-05-05)