perf bpf-utils: Constify bpil_array_desc

The array's contents is a compile time constant. Constify to make the
code more intention revealing and avoid unintended errors.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250902181713.309797-3-irogers@google.com


Signed-off-by: Namhyung Kim <namhyung@kernel.org>