Follow the steps: https://github.com/facebook/zstd/blob/v1.5.6/contrib/linux-kernel/README.md
The following committed changes are also preserved:
c97320470b510a90bac077842630bd49c7cce95e zstd: merge optimization from Samsung <DevriesL>
9df1909b60b40fc7450ebff9b45d7cd2ac70225d lib: zstd: Don't inline functions in zstd_opt.c <Nick Terrell>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>