[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.

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