[clang] [X86][AVX10] Re-target mavx10.1 and emit warning for mavx10.x-256/512 and m[no-]evex512 (PR #132542)

[Simon Pilgrim via cfe-commits]

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

LGTM - but we need to add a full explanation to the clang/llvm release notes explaining the avx10 changes/deprecations (and future removal).

https://github.com/llvm/llvm-project/pull/132542