tools: bpftool: teach cfg code about JMP32

mainline inclusion
from mainline-v5.1-rc1
commit df791dc1
category: bugfix
bugzilla: NA
CVE: CVE-2021-3444

--------------------------------

The cfg code need to be aware of the new JMP32 instruction class so it
could partition functions correctly.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: He <Fengqing&lt;hefengqing@huawei.com>
Reviewed-by: Kuohai Xu <xukuohai@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>