[PATCH] Kernel bitbake recipe: use FILESEXTRAPATHS instead of FILESPATH

When trying to override for example a kernel configuration file
(defconfig) from a bbappend file according to the yocto kernel
documentation this fails together with the meta-beagleboard layer.

In order to be able to use this suggested approach from a bbappend file:


to insert extra paths before the paths from the meta-beagleboard layer
itself the recipe should not set FILESPATH directly. This patch changes the
recipe to use FILESEXTRAPATHS instead.

This patch was developed and tested against the 3.8 branch, might apply
to other branches as well (?)

Signed-off-by: Daniel Nilsson <daniel@dnil.se>