[PATCH] arm64: use vma_pages helper

[Allen]

>>    Use vma_pages function on vma object instead of explicit computation.
>>    This is a clean up patch.
>
> A version of this is already queued for -next here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?h=for-next/core&id=b4f4a2755665bf847231050b569f587ce0945482
>
  Ah. Please ignore the patch.

Thanks.