Add a 'layer' target containing all the data that will be used to
generate a generic yocto layer.
(From meta-yocto rev: 198a85f61ebd6435830285b2a9b1b925aea6779e)
Signed-off-by: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>