[build] Clean up redundant LTO configs in starnix

We enabled Rust LTO by default in release mode via
https://fxrev.dev/1454713. This CL removes the now-redundant
lto-rust-linker-plugin from kernel_library_config and
thinlto-if-not-enabled from vdso_config, as these are now
handled by the global default.

Bug: 457537341
Change-Id: I8f3dec1dfd8b131aa24677e9b4e2fdef32d42a2d
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1458794
Reviewed-by: Benjamin Lerman <qsr@google.com>
Commit-Queue: Gulfem Savrun Yeniceri <gulfem@google.com>
Fuchsia-Auto-Submit: Gulfem Savrun Yeniceri <gulfem@google.com>
2 files changed