Integrate meta-seconorth-mtk/u-boot_patches

Commit: seco-ne/yocto/layers/meta-seconorth-mtk@bf31188a

recipes: Remove u-boot patches

They were applied directly to source code to be able to build the image after using 'devtool modify u-boot-seco-mtk' and commit changes directly to source code and not create patch files. Otherwise, you need to keep the 'devtool' branch with applied patches and separately commit to a feature-branch