hugetlb:fix build error

the error message is as follow:

../arch/loongarch/mm/mmap.c: In function ‘arch_get_unmapped_area_common’:
../arch/loongarch/mm/mmap.c:69:35: error: implicit declaration of function ‘huge_page_mask_align’; did you mean ‘huge_page_mask’? [-Werror=implicit-function-declaration]
   69 |                 info.align_mask = huge_page_mask_align(filp);
      |                                   ^~~~~~~~~~~~~~~~~~~~
      |                                   huge_page_mask
cc1: some warnings being treated as errors

code sync for linux-6.13

Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>

include/linux/hugetlb.h

@@ -1035,6 +1035,11 @@ void hugetlb_unregister_node(struct node *node);
  */
 bool is_raw_hwpoison_page_in_hugepage(struct page *page);
 
+static inline unsigned long huge_page_mask_align(struct file *file)
+{
+	return PAGE_MASK & ~huge_page_mask(hstate_file(file));
+}
+
 #else	/* CONFIG_HUGETLB_PAGE */
 struct hstate {};