Branch to start enablement of bsps. Kernel recipes. Uboot recipes. Zedboard meta layer.

Signed-off-by: Sipke Vriend <sipke.vriend@xilinx.com>
Refactor zedboard machine. Move commone items into tune-zynq include file.

Signed-off-by: Sipke Vriend <sipke.vriend@xilinx.com>
Moved defconfig to bsp/board layer.
Also some other minor changes.

Signed-off-by: Sipke Vriend <sipke.vriend@xilinx.com>