genorig should not be done in development workflows when running locally

[fwilhe]

Discussed with @Vincinator and @nkraetzschmar

Here

package-linux/prepare_source

Line 18 in f331bc9

debian/bin/genorig.py --override-version "$version_orig" "$kernel_repo"

we are cloning the kernel each time we call the prepare_source script. This is not good for local development as it takes a few minutes each time which makes the workflow for fixing patches harder.

It would be nice if we could avoid doing this each time for a local development setup. We should still avoid a 'dirty' state, i.e. applied patches need to be accounted for.