tools/build: Remove some unused libbpf pre-1.0 feature test logic

tools/build: Remove some unused libbpf pre-1.0 feature test logic

Commit 76a97cf2e169 ("perf build: Remove libbpf pre-1.0 feature
tests") removed the libbpf feature test logic used by perf in favor of
using LIBBPF_MAJOR_VERSION. Remove some build targets that should have
been removed as part of that clean up.

Fixes: 76a97cf2e169 ("perf build: Remove libbpf pre-1.0 feature tests")
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250603221358.2562167-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>