add kernel/.gitignore

hc

2024-08-16 a24a44ff9ca902811b99aa9663d697cf452e08ef

external/rknpu2/examples/3rdparty/opencv/OpenCV-android-sdk/sdk/native/3rdparty/libs/arm64-v8a/liblibprotobuf.a does not exist in tree 091a6a990842ffe8e9cc4b5a936157281d32f01b