kbuild: Add skip_encoding_btf_enum64 option to pahole

New pahole (version 1.24) generates by default new BTF_KIND_ENUM64 BTF tag,
which is not supported by stable kernel.

As a result the kernel with CONFIG_DEBUG_INFO_BTF option will fail to
compile with following error:

  BTFIDS  vmlinux
FAILED: load BTF from vmlinux: Invalid argument

New pahole provides --skip_encoding_btf_enum64 option to skip BTF_KIND_ENUM64
generation and produce BTF supported by stable kernel.

Adding this option to scripts/pahole-flags.sh.

This change does not have equivalent commit in linus tree, because linus tree
has support for BTF_KIND_ENUM64 tag, so it does not need to be disabled.

Signed-off-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

scripts/pahole-flags.sh

@@ -14,4 +14,8 @@ if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then
 	extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars"
 fi
 
+if [ "${pahole_ver}" -ge "124" ]; then
+	extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_enum64"
+fi
+
 echo ${extra_paholeopt}