Auto merge of #135015 - heiher:stabilize-loongarch-target-features, r=Amanieu

Partially stabilize LoongArch target features

Stabilization PR for the LoongArch target features. This PR stabilizes some of the target features tracked by #44839.

Specifically, this PR stabilizes the following target features:

* f
* d
* frecipe
* lasx
* lbt
* lsx
* lvz

Docs PR: https://github.com/rust-lang/reference/pull/1707

r? `@Amanieu`