Fix comments of __get_user_pages() and get_user_pages_remote(), make
them more clear.

Link: http://lkml.kernel.org/r/1572443533-3118-1-git-send-email-liuxiang_1999@126.comSigned-off-by: NLiu Xiang <liuxiang_1999@126.com>
Suggested-by: NJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>