bblayers.conf.sample: Adopt to meta-xilinx restructuring
bblayers.conf.sample: Adopt to meta-xilinx restructuring

Adopt to meta-xilinx restructuring to include meta-xilinx-bsp and
meta-xilinx-contrib layers

Signed-off-by: Manjukumar Matha <4c64a17569570cb9f1048973bce031c402b55312@xilinx.com>

Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux