crypto: sahara - use the backlog

With commit

	7e77bdeb crypto: af_alg - fix backlog handling

in place, the backlog works under all circumstances where it previously failed, atleast
for the sahara driver. Use it.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>