mm: move is_vma_temporary_stack() declaration to huge_mm.h

When transparent_hugepage_enabled() is used outside mm/, such as in
arch/x86/xx/tlb.c:

+       if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB
+                       || transparent_hugepage_enabled(vma)) {
+               flush_tlb_mm(vma->vm_mm);

is_vma_temporary_stack() isn't referenced in huge_mm.h, so it has compile
errors:

  arch/x86/mm/tlb.c: In function `flush_tlb_range':
  arch/x86/mm/tlb.c:324:4: error: implicit declaration of function `is_vma_temporary_stack' [-Werror=implicit-function-declaration]

Since is_vma_temporay_stack() is just used in rmap.c and huge_memory.c, it
is better to move it to huge_mm.h from rmap.h to avoid such errors.
Signed-off-by: Alex Shi <alex.shi@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/huge_mm.h

@@ -59,6 +59,8 @@ extern pmd_t *page_check_address_pmd(struct page *page,
 #define HPAGE_PMD_MASK HPAGE_MASK
 #define HPAGE_PMD_SIZE HPAGE_SIZE
 
+extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
+
 #define transparent_hugepage_enabled(__vma)				\
 	((transparent_hugepage_flags &					\
 	  (1<<TRANSPARENT_HUGEPAGE_FLAG) ||				\

include/linux/rmap.h

@@ -173,8 +173,6 @@ enum ttu_flags {
 };
 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
 
-bool is_vma_temporary_stack(struct vm_area_struct *vma);
-
 int try_to_unmap(struct page *, enum ttu_flags flags);
 int try_to_unmap_one(struct page *, struct vm_area_struct *,
 			unsigned long address, enum ttu_flags flags);