sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   53435562a725962e4de0c29653223129ba11643a
Checkpoint bpf-next commit: 9a3a07d06e7d74f4aecc51396c771149336ac55d
Baseline bpf commit:        9b51a6155d14389876916726430da30eabb1d4ed
Checkpoint bpf commit:      7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f

Daniel Borkmann (1):
  libbpf: Drop in-loader metadata check for load-time verification

Jiri Olsa (1):
  bpf: Add tracing_multi link info support

Naveed Khan (1):
  libbpf: Fix double-free of distilled base BTF on .BTF.ext parse error

Yuan Chen (1):
  libbpf: Skip bpf_object__probe_loading() when BPF token is in use

 include/uapi/linux/bpf.h |  9 +++++
 src/bpf_gen_internal.h   |  1 -
 src/btf.c                | 10 +++---
 src/gen_loader.c         | 76 ++++------------------------------------
 src/libbpf.c             | 10 ++----
 src/libbpf_internal.h    |  1 -
 src/skel_internal.h      | 31 ++--------------
 7 files changed, 26 insertions(+), 112 deletions(-)

Signed-off-by: Song Liu <song@kernel.org>

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-9b51a6155d14389876916726430da30eabb1d4ed
+7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f

CHECKPOINT-COMMIT

@@ -1 +1 @@
-53435562a725962e4de0c29653223129ba11643a
+9a3a07d06e7d74f4aecc51396c771149336ac55d