kbuild: canonicalization of target path not needed anymore

In Rust-for-Linux#272 `realpath`
was added to work around a bug in `rustdoc`, but it is not needed
anymore since rust-lang/rust#85361, i.e.
since Rust 1.54.0.

Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

scripts/Makefile.build

@@ -328,10 +328,7 @@ $(obj)/%.lst: $(src)/%.c FORCE
 # Compile Rust sources (.rs)
 # ---------------------------------------------------------------------------
 
-# Need to use absolute path here and have symbolic links resolved;
-# otherwise rustdoc and rustc compute different hashes for the target.
-rust_cross_flags := --target=$(realpath $(KBUILD_RUST_TARGET))
-
+rust_cross_flags := --target=$(KBUILD_RUST_TARGET)
 rust_allowed_features := allocator_api,bench_black_box,concat_idents,generic_associated_types
 
 rust_common_cmd = \