Merge branch 'bpf: __bpf_dynptr_data* and __str annotation'

Merge branch 'bpf: __bpf_dynptr_data* and __str annotation'

Song Liu says:

====================
This set contains the first 3 patches of set [1]. Currently, [1] is waiting
for [3] to be merged to bpf-next tree. So send these 3 patches first to
unblock other works, such as [2]. This set is verified with new version of
[1] in CI run [4].

Changes since v12 of [1]:
1. Reuse bpf_dynptr_slice() in __bpf_dynptr_data(). (Andrii)
2. Add Acked-by from Vadim Fedorenko.

[1] https://lore.kernel.org/bpf/20231104001313.3538201-1-song@kernel.org/
[2] https://lore.kernel.org/bpf/20231031134900.1432945-1-vadfed@meta.com/
[3] https://lore.kernel.org/bpf/20231031215625.2343848-1-davemarchevsky@fb.com/
[4] https://github.com/kernel-patches/bpf/actions/runs/6779945063/job/18427926114
====================

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