* Improve by changing from legacy extraConfig to the
structuredExtraConfig style kerenl configuration.
* Remove few unneeded kernel modules from default configuration.
* Make kernelPatches, structuredExtraConfig and extraMeta overrideable.
* Change callPackage-style function to actually take the individual
attributes from pkgs.
* Get rid of recursive syntax.
Signed-off-by: Mika Tammi <mika.tammi@unikie.com>