crypto: engine - Use crypto_request_complete

[ Upstream commit 6909823d ]

Use the crypto_request_complete helper instead of calling the
completion function directly.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Stable-dep-of: 4140aafc ("crypto: engine - fix crypto_queue backlog handling")
Signed-off-by: Sasha Levin <sashal@kernel.org>