[clang] [llvm] [RISCV] Add TT-Ascalon-d8 processor (PR #115100)

[Min-Yih Hsu via cfe-commits]

https://github.com/mshockwave approved this pull request.

LGTM.
I don't have any strong opinion on the CPU name

https://github.com/llvm/llvm-project/pull/115100