[compiler-rt] [compiler-rt][Mips] Align definition of __sanitizer_sigaction with musl (PR #124494)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

Lets wait a little for @MaskRay who previously reviews MUSL.
If you no response please request review from me again and I'll merge the patch.

https://github.com/llvm/llvm-project/pull/124494