Integrate meta-seconorth-distro/fix_copy_fnginstall

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Commit: seco-ne/yocto/layers/meta-seconorth-distro@db2988c5

fng-install:self-update: Added missing -r option to copy

The fngsystem-self-update runs the post-install steps on a temporary
directory and copies the files afterwards to the Flash-N-Go System
partition. We now have an optional overlays folder which also needs
to be copied and therefore need the recursive (-r) option on the
cp call.