crypto: scatterwalk - Fix test in scatterwalk_done

crypto: scatterwalk - Fix test in scatterwalk_done

[ Upstream commit 5f070e81bee35f1b7bd1477bb223a873ff657803 ]

When there is more data to be processed, the current test in
scatterwalk_done may prevent us from calling pagedone even when
we should.

In particular, if we're on an SG entry spanning multiple pages
where the last page is not a full page, we will incorrectly skip
calling pagedone on the second last page.

This patch fixes this by adding a separate test for whether we've
reached the end of a page.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
(cherry picked from commit 812925986c9f0398f9a15228580cf4d38fdd1577)
Signed-off-by: Todd Vierling <todd.vierling@oracle.com>
Reviewed-by: Ethan Zhao <ethan.zhao@oracle.com>