plugins/micron: clamp num_entries in vs-fw-activate-history to the table size

[prabhakarpujeri]

Summary

num_entries in the micron fw activation history log page is device-supplied.
Both printers used it as the loop bound (without even le32_to_cpu()) against
the fixed entries[20] table in struct micron_fw_activation_history_table,
which lives inside the 4096-byte log page:

for (count = 0; count < table->num_entries; count++) {
    if (!display_fw_activate_entry(count, &table->entries[count],
            formatted_output, sizeof(formatted_output), NULL))
        printf("%s
", formatted_output);
}

A device reporting a count above 20 runs both loops past the array, emitting
bytes past the log buffer into stdout or into the JSON envelope.

This is the exact same pattern as #3993 (seagate fw-activate-history entry-count
clamp) that igaw merged on 2026-09-08.

Fix

Clamp table->num_entries to ARRAY_SIZE(table->entries) right after the
existing version/log-page validation, so both views see the bounded value. The
clamp also applies le32_to_cpu/cpu_to_le32 at that point.

Testing

• meson setup build-main && ninja -C build-main: clean.
• Hostile-input harness (ASan+UBSan) with num_entries = 0xFFFFFFFF:
  • pre-fix: heap-buffer-overflow — read of size 1 at 52 bytes past a
    4116-byte allocation;
  • post-fix: loop runs exactly 20 iterations, exit 0.

[igaw]

Thanks!