mm/page_alloc.c: modify the comment section for alloc_contig_pages()

Clarify that the alloc_contig_pages() allocated range will always be
aligned to the requested nr_pages.

Link: https://lkml.kernel.org/r/1639545478-12160-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -9272,8 +9272,8 @@ static bool zone_spans_last_pfn(const struct zone *zone,
  * for allocation requests which can not be fulfilled with the buddy allocator.
  *
  * The allocated memory is always aligned to a page boundary. If nr_pages is a
- * power of two then the alignment is guaranteed to be to the given nr_pages
- * (e.g. 1GB request would be aligned to 1GB).
+ * power of two, then allocated range is also guaranteed to be aligned to same
+ * nr_pages (e.g. 1GB request would be aligned to 1GB).
  *
  * Allocated pages can be freed with free_contig_range() or by manually calling
  * __free_page() on each allocated page.