[nrf fromtree] sysbuild: Allow to use file suffix DTS overlays#2929

nordicjm merged 2 commits intonrfconnect:mainnrfconnect/sdk-zephyr:mainfrom

tomchy:bugfix/sysbuild/NCSDK-NONE_Allow_to_add_suffix_overlaystomchy/sdk-zephyr:bugfix/sysbuild/NCSDK-NONE_Allow_to_add_suffix_overlaysCopy head branch name to clipboard