hugetlb: show nr_huge_pages in report_hugepages()

The number of pre-allocated huge pages should be nr_huge_pages, not
free_huge_pages, although they are same during booting stage

Link: https://lkml.kernel.org/r/20250515114231.65824-1-xuwenjie04@baidu.com


Signed-off-by: Wenjie Xu <xuwenjie04@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>