kernel.bbclass: Ensure kernel/* internal sysroot working directory don't get packaged
kernel.bbclass: Ensure kernel/* internal sysroot working directory don't get packaged

This removes a couple of megabytes of QA warnings!

Signed-off-by: Richard  Purdie <3b7a1db6efedd40440bc6443bf377195011524e5@linuxfoundation.org>
Signed-off-by: Koen Kooi <42e3d96910f922bdd7dd1805fe3f8aff634f391d@dominion.thruhere.net>

WindRiver-OpenSourceLabs/meta-oe-subset,WindRiver-OpenSourceLabs/meta-oe-subset