This patch cleans up btf.h in uapi:
1) Rename "name" to "name_off" to better reflect it is an offset to the
   string section instead of a char array.
2) Remove unused value BTF_FLAGS_COMPR and BTF_MAGIC_SWAP
Suggested-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>