[clang] [llvm] [RISCV] Remove duplicate extensions from tt-ascalon-d8 CPU (PR #137865)

[Sam Elliott via cfe-commits]

lenary wrote:

If the `"-target-feature" "+sscofpmf"` was already present in the test output, just not looked for, then I think you should just mark this as `[NFC]`.

https://github.com/llvm/llvm-project/pull/137865