hugetlb: optimise hugetlb_folio_init_tail_vmemmap()

hugetlb: optimise hugetlb_folio_init_tail_vmemmap()

Extract the zone number directly from the folio instead of using the
folio's zone number to look up the zone and asking the zone what its
number is.

Also we should use &folio->page instead of casting from folio to page

Link: https://lkml.kernel.org/r/20251106201452.2292631-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>