[OE-core] [CONSOLIDATED PULL 29/43] package.bbclass: Ensure kernel modules get stripped

[Dominik]

> Kernel modules are not marked as executable but we do expect to strip them.
> This patch adds in missing code to ensure we do this. Without this images
> are getting sigificantly bloated in size.
> 


This patch causes problems with TI's dsplink and linuxutils as posted here 
http://comments.gmane.org/gmane.linux.embedded.yocto.meta-ti/340.