mm/huge_memory.c: fix comment in __split_huge_pmd_locked

pmd_trans_splitting() was removed after THP refcounting redesign,
therefore related comment should be updated.

Link: http://lkml.kernel.org/r/1512625745-59451-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

@@ -2205,10 +2205,9 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 	 * for the same virtual address to be loaded simultaneously. So instead
 	 * of doing "pmd_populate(); flush_pmd_tlb_range();" we first mark the
 	 * current pmd notpresent (atomically because here the pmd_trans_huge
-	 * and pmd_trans_splitting must remain set at all times on the pmd
-	 * until the split is complete for this pmd), then we flush the SMP TLB
-	 * and finally we write the non-huge version of the pmd entry with
-	 * pmd_populate.
+	 * must remain set at all times on the pmd until the split is complete
+	 * for this pmd), then we flush the SMP TLB and finally we write the
+	 * non-huge version of the pmd entry with pmd_populate.
 	 */
 	pmdp_invalidate(vma, haddr, pmd);
 	pmd_populate(mm, pmd, pgtable);