Fix: Replace pn-defaultpkgname with ${PN}

[deribaucourt]

The overrides are scanned using no specific recipe. The corresponding package override, pn-defaultpkgname does not exist in this case. Commonly, ${PN} is used instead.

[rossburton]

Inside a recipe you'd never use pn-${PN} as there's no point: you're already in recipe-scope.

Outside of a recipe you'd need to use the full recipe name, not PN.

So maybe just remove pn-defaultpkgname>

[deribaucourt]

Inside a recipe you'd never use pn-${PN} as there's no point: you're already in recipe-scope.

@rossburton With this PR, we just suggest ${PN}, it's very useful when defining the FILES variable for instance:

Outside of a recipe you'd need to use the full recipe name, not PN.

So maybe just remove pn-defaultpkgname>

Yeah it doesn't makes that much sense outside of a recipe. Yet theoretically I think it can be used in .inc/.bbclass files to refer to the actual PN that will be used by the recipes. If this suggestion really hurts hurts, we may add logic to detect if we're in a .conf file to disable it.

Otherwise, I think ${PN} is a valuable as suggestion in general like in the FILES variable example.