[oe] iproute2: Remove undocumented bash runtime dependency, move to INC_PR and rework dir layout

[Marc Olzheim]

I noticed that iproute2 has a runtime dependency on bash in two of its scripts.
Those dependencies are unneeded, so I removed them.

Before doing that though, I moved the recipes to INC_PR and changed the
directory layout to prevent useless duplication of the patches in the
directories.

I hope that this is the way to go.

Marc