sync: latest libbpf changes from kernel

Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   3e6fe5ce4d4860c3a111c246fddc6f31492f4fb0
Checkpoint bpf-next commit: bb7a4257892717caf82fe6da45b259b35f73445c
Baseline bpf commit:        5e0b0a4c52d30bb09659446f40b77a692361600d
Checkpoint bpf commit:      a2b1a5d40bd12b44322c2ccd40bb0ec1699708b6

Delyan Kratunov (1):
  libbpf: add support for sleepable uprobe programs

Maxim Mikityanskiy (2):
  bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
  bpf: Add helpers to issue and check SYN cookies in XDP

 include/uapi/linux/bpf.h | 88 ++++++++++++++++++++++++++++++++++++++--
 src/libbpf.c             |  5 ++-
 2 files changed, 88 insertions(+), 5 deletions(-)

--
2.30.2

BPF-CHECKPOINT-COMMIT

@@ -1 +1 @@
-5e0b0a4c52d30bb09659446f40b77a692361600d
+a2b1a5d40bd12b44322c2ccd40bb0ec1699708b6

CHECKPOINT-COMMIT

@@ -1 +1 @@
-3e6fe5ce4d4860c3a111c246fddc6f31492f4fb0
+bb7a4257892717caf82fe6da45b259b35f73445c