Remove unnecessary [lints.rust] sections.

`bootstrap` and `llvm_enzyme` are now both in the extra `check-cfg` list
in bootstrap, so they doesn't need to be handled explicitly in
`Cargo.toml` files.

compiler/rustc_builtin_macros/Cargo.toml

@@ -3,10 +3,6 @@ name = "rustc_builtin_macros"
 version = "0.0.0"
 edition = "2024"
 
-
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(llvm_enzyme)'] }
-
 [lib]
 doctest = false
 

compiler/rustc_type_ir/Cargo.toml

@@ -33,6 +33,3 @@ nightly = [
     "rustc_index/nightly",
     "rustc_ast_ir/nightly",
 ]
-
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(bootstrap)'] }