CVE-2025-39727 – mm: swap: fix potential buffer overflow in setup_clusters()

In the Linux kernel, the following vulnerability has been resolved:

mm: swap: fix potential buffer overflow in setup_clusters()

In setup_swap_map(), we only ensure badpages are in range (0, last_page].
As maxpages might be = maxpages.

Only call inc_cluster_info_page() for badpage which is < maxpages to fix
the issue.