crypto: af_alg - use DIV_ROUND_UP helper macro for calculations

Replace open coded divisor calculations with the DIV_ROUND_UP kernel
macro for better readability.
Signed-off-by: NWu Bo <wubo40@huawei.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto/af_alg.c

@@ -411,7 +411,7 @@ int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 	if (n < 0)
 		return n;
 
-	npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
 	if (WARN_ON(npages == 0))
 		return -EINVAL;
 	/* Add one extra for linking */