There is a prologue on page fault handler which marking pages dirty
and/or accessed in page attributes, but all of these have been
handled in handle_pte_fault.

 - Add flush_tlb_one in vmalloc page fault instead of prologue.
 - Using cmxchg_fixup C codes in do_page_fault instead of ASM one.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>