Merge branch 'bpf-add-bpf_dynptr_memset-kfunc'

Ihor Solodrai says:

====================
bpf: add bpf_dynptr_memset() kfunc

Implement bpf_dynptr_memset() kfunc and add tests for it.

v3->v4:
  * do error checks after slice, nits
v2->v3:
  * nits and slow-path loop rewrite (Andrii)
  * simplify xdp chunks test (Mykyta)
v1->v2:
  * handle non-linear buffers with bpf_dynptr_write()
  * change function signature to include offset arg
  * add more test cases

v3: https://lore.kernel.org/bpf/20250630212113.573097-1-isolodrai@meta.com/
v2: https://lore.kernel.org/bpf/20250624205240.1311453-1-isolodrai@meta.com/
v1: https://lore.kernel.org/bpf/20250618223310.3684760-1-isolodrai@meta.com/
====================

Link: https://patch.msgid.link/20250702210309.3115903-1-isolodrai@meta.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>