Convert all nfs base tests to ramdisk based for ARM64 systems.

Hi Team,

I am planning to rise a change to convert all nfs roofs based tests to ramdisk based.

Following is the first list :

1. kselftest-breakpoints-ramdisk
2. kselftest-capabilities-ramdisk
3. kselftest-clone3-ramdisk
4. kselftest-coredump-ramdisk
5. kselftest-cpufreq-ramdisk
6. kselftest-dmabuf-heaps-ramdisk
7. kselftest-dt-ramdisk
8. kselftest-efivars-ramdisk
9. kselftest-exec-ramdisk
10. kselftest-ftrace-ramdisk
11. kselftest-futex-ramdisk
12. kselftest-gpio-ramdisk
13. kselftest-iommu-ramdisk
14. kselftest-perf-events-ramdisk
15. kselftest-proc-ramdisk
16. kselftest-ring-buffer-ramdisk
17. kselftest-timers-ramdisk
18. kselftest-tmpfs-ramdisk

Start by locating the configurations for the listed kselftest entries, from kselftest-breakpoints-ramdisk through kselftest-tmpfs-ramdisk, and inspect how their current NFS-root setup is defined. Convert the listed tests to ramdisk-based operation for ARM64, then verify that every entry in the list uses the new base and still runs successfully.

Written by the indexing model from the issue text.