recipes-kernel:dtbo: Cleanup dtbo directory and add csm-b79 overlay
All these dtbo files are not needed in machine layer, as they are pulled from meta-mediatek-bsp layer. Only seco-specific files should stay in this layer.
All these dtbo files are not needed in machine layer, as they are pulled from meta-mediatek-bsp layer. Only seco-specific files should stay in this layer.