sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   1bba3b3d373dbafae891e7cb06b8c82c8d62aba1
Checkpoint bpf-next commit: 0737df6de94661ae55fd3343ce9abec32c687e62
Baseline bpf commit:        b867247555c4181bf84eb10b72b176862c29112d
Checkpoint bpf commit:      3e9bc0472b910d4115e16e9c2d684c7757cb6c60

Andrii Nakryiko (1):
  libbpf: better fix for handling nulled-out struct_ops program

Jiri Olsa (3):
  bpf: Add support for kprobe session attach
  libbpf: Add support for kprobe session attach
  libbpf: Add kprobe session attach type name to attach_type_name

Viktor Malik (1):
  libbpf: support "module: Function" syntax for tracing programs

 include/uapi/linux/bpf.h |   1 +
 src/bpf.c                |   1 +
 src/libbpf.c             | 112 +++++++++++++++++++++++++++++++--------
 src/libbpf.h             |   4 +-
 4 files changed, 95 insertions(+), 23 deletions(-)

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-b867247555c4181bf84eb10b72b176862c29112d
+3e9bc0472b910d4115e16e9c2d684c7757cb6c60

CHECKPOINT-COMMIT

@@ -1 +1 @@
-1bba3b3d373dbafae891e7cb06b8c82c8d62aba1
+0737df6de94661ae55fd3343ce9abec32c687e62