Rollup merge of #138084 - nnethercote:workspace-lints, r=jieyouxu

Use workspace lints for crates in `compiler/`

This is nicer and hopefully less error prone than specifying lints via bootstrap.

r? ``@jieyouxu``

compiler/rustc_llvm/Cargo.toml

@@ -14,3 +14,6 @@ libc = "0.2.73"
 # pinned `cc` in `rustc_codegen_ssa` if you update `cc` here.
 cc = "=1.2.16"
 # tidy-alphabetical-end
+
+[lints]
+workspace = true

compiler/rustc_llvm/src/lib.rs

@@ -4,7 +4,6 @@
 #![doc(rust_logo)]
 #![feature(extern_types)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 use std::cell::RefCell;