add kernel/.gitignore

hc

2024-08-16 a24a44ff9ca902811b99aa9663d697cf452e08ef

prebuilts/gcc/linux-x86/aarch64/gcc-arm-10.3-2021.07-x86_64-aarch64-none-linux-gnu/aarch64-none-linux-gnu/lib64/libstdc++.a does not exist in tree 091a6a990842ffe8e9cc4b5a936157281d32f01b