Merge branch 'libbpf-remove-extern-declaration-of-bpf_stream_vprintk'

Ihor Solodrai says:

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libbpf: Remove extern declaration of bpf_stream_vprintk()

The first patch adjusts a selftest that has been using
bpf_stream_printk() macro. The second patch removes the declaration.
====================

Link: https://patch.msgid.link/20260218215651.2057673-1-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>