change redundant transmutations of sign to cast_unsigned

[bend-n]

fix redundant transmutations

warning: this transmute could be performed safely
     --> crates/core_arch/src/x86/avx512f.rs:29273:5
      |
29273 |     transmute(r)
      |     ^^^^^^^^^^^^ help: replace `transmute`: `i8::cast_unsigned(r)`

(many (24) such cases, this one is a transmute of i8 -> __mmask8)

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Amanieu (or someone else) some time within the next two weeks.

[sayantn]

I think it would be better to replace those than allow the lint. It doesn't seem like too much work - only 24 instances

[bend-n]

@sayantn

you mean for me to actually cargo fix those warnings?

[sayantn]

Imo that would be better, and the lint will actually serve its purpose

[bend-n]

erm, okay. done (the nightly feature will stabilize on nightly soon)

[bend-n]

should be stable by next nightly