[clang] [llvm] [RISCV] Add Andes AX45MPV processor definition (PR #145267)

[Min-Yih Hsu via cfe-commits]

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+// RUN: %clang --target=riscv64 -mcpu=andes-ax45mpv --print-enabled-extensions | FileCheck %s
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mshockwave wrote:

I believe this is also what AArch64 does

https://github.com/llvm/llvm-project/pull/145267