Link warning when enabling LTO for native simulator based targets

[aescolar]

Describe the bug
If CONFIG_LTO is set, the partial link done for native simulator based targets will produce a warning.
This warning is due to mixing objects built with and without LTO enabled, and informs the users that
LTO will be ignored.

To Reproduce
Steps to reproduce the behavior:

1. mkdir build; cd build
2. cmake -GNinja -DBOARD=native_sim ../samples/hello_world/ -DCONFIG_LTO=y
3. ninja
4. See warning

Expected behavior
No link warnings

Impact
twister/CI failures for samples/tests which enable LTO in their default configuration

Logs and console output
See for example this CI failure for a PR which attempted to enable LTO in the configuration of a sample:
https://github.com/zephyrproject-rtos/zephyr/actions/runs/7816163519/job/21321300058?pr=68694#step:13:897

Environment (please complete the following information):

• OS: Linux Ubuntu 22.04/CI
• Toolchain (e.g Zephyr SDK, ...): gcc 11 or 12
• Commit SHA or Version used: Today's main b30d088

Additional context
The feature was introduced in #66392